JP7101384B2 - Joining method - Google Patents

Description

The present invention relates to a joining method, and more particularly to a joining method of joining materials to be joined by utilizing the reaction heat of an exothermic material and a joined body joined by the joining method.

A joining method is known in which the materials to be joined are joined to each other by using the heat of reaction generated by the thermite reaction or the self-combustion reaction. In the above joining method, the reaction propagates and heat is generated only by first applying energy, so that continuous external heat supply is not required.

In Japanese Patent Application Laid-Open No. 2003-531758, Ni foil and Al foil are alternately laminated, and the rolled reactive multilayer foil is bonded by utilizing the heat generated by the self-fuel reaction between Ni and Al. It is stated that it is possible.

Special Table 2003-531758 Gazette

However, when the heat of reaction of the self-fuel synthesis reaction such as the reaction of Ni and Al is used to join structurally bonded materials such as steel materials and aluminum alloy materials, unreacted reaction materials tend to remain. Further, the heat of reaction is not uniformly transmitted to the material to be joined, and voids and the like are likely to be generated at the joining interface, and the joining strength is lowered.

The present invention has been made in view of the problems of the prior art, and the purpose of the present invention is to provide a uniform and highly adhesive bonding interface in which no unreacted reactant remains at the bonding interface. The purpose is to provide a joining method that can be formed.

As a result of diligent studies to achieve the above object, the present inventor has found that the above object can be achieved by optimizing the heat generation duration of the reaction and uniformly transmitting the heat of reaction to the material to be bonded. The invention was completed.

That is, the joining method of the present invention is a joining method in which the exothermic material between the materials to be joined is generated to generate heat and the above-mentioned materials to be joined are joined to each other.
The exothermic material contains a self-combustion synthetic reaction material and a thermite reaction material, and has a low melting point metal material on a contact surface with at least one of the materials to be joined.
The melting point of the low melting point metal material is equal to or lower than the melting point of both bonded materials to be bonded.

Further, the joined body of the present invention is formed by joining a plurality of materials to be joined by the above-mentioned joining method.
Then, the reaction product of the thermite reaction material, the reaction product of the self-combustion synthetic reaction material, and the low melting point metal are contained at the interface between the materials to be joined.
The melting point of the low melting point metal material is equal to or lower than the melting point of both of the materials to be joined.

According to the present invention, the exothermic material contains a self-burning synthetic reaction material and a thermite reaction material, and a low melting point metal material is provided on a contact surface with at least one of the materials to be joined to generate the exothermic material. Therefore, it is possible to provide a bonding method capable of forming a uniform and highly adhesive bonding interface without leaving an unreacted reaction material on the bonding interface.

It is sectional drawing which shows an example of the layer structure of the exothermic material. It is a cross-sectional SEM image of the junction interface of the junction of Example 1. 6 is a cross-sectional SEM image of the joining interface of the joining body of Example 9. It is a cross-sectional SEM image of the junction interface of the junction of Example 10.

The joining method of the present invention will be described in detail.
The above-mentioned joining method is a joining method in which a part of the material to be joined is melted by the heat of reaction to be joined. conduct.

As shown in FIG. 1, the exothermic material 1 contains a self-combustion synthetic reaction material 4 and a thermite reaction material 3, and has a low melting point metal material 2 on a contact surface with at least one of the materials to be joined.

In the self-combustion synthesis reaction, the reaction is generally mild and heat generation continues for a long time to easily melt the joint surface of the material to be joined, but the activation energy is high. Therefore, in order to initiate the reaction, high energy such as by a laser is required, and inexpensive bonding is difficult.

In the joining method using the heat of reaction described above, energy is applied from the end of the joining surface to propagate the reaction in the in-plane direction of the joining surface, so that the propagation distance is inevitably long and the self-combustion synthesis reaction is carried out on the joining surface. It is difficult to propagate to the entire surface, and unreacted self-burning synthetic reactants tend to remain.

In the thermite reaction, the propagation speed of the reaction is very fast and the reaction is completed in an instant. Therefore, the temperature rises and falls rapidly, it is difficult for heat to be transferred uniformly to the material to be bonded, uniform bonding is difficult, and voids are likely to occur. While the adhesion is lowered, the activation energy is lower than that of the self-burning synthesis reaction. Therefore, for example, electric discharge can be used to start the reaction, and inexpensive bonding is possible.

In the present invention, an exothermic material containing a self-burning synthetic reaction material and a thermite reaction material is used. Therefore, since the self-burning synthesis reaction can be induced by the reaction heat of the thermite reaction, it is sufficient to add the energy for initiating the thermite reaction, and high energy is not required.

In addition, as shown in FIG. 1, the exothermic material is a layered layer of the self-combustion synthetic reaction material and the thermite reaction material, so that the self-combustion synthetic reaction starts from the end of the joint surface and is formed on the joint surface. Rather than propagating towards the center of, the thermite reaction initiates at about the same time on the entire surface of the junction. Therefore, the self-combustion synthesis reaction propagates in the out-of-plane direction of the joint surface, that is, in the thickness direction of the exothermic material, so that the propagation distance becomes short.

Furthermore, the heat of reaction of the self-burning synthesis reaction and the heat of reaction of the thermit reaction induce each other's reaction, and the self-burning synthesis reaction and the thermit reaction propagate respectively. It is possible to prevent the generation of a reactant.

Further, even if the exothermic material and the material to be joined are brought into close contact with each other, microscopic voids are likely to occur at the contact interface between the solid and the solid, and it is difficult to completely adhere the exothermic material and the material to be joined. .. Therefore, the heat conduction path from the exothermic material to the material to be joined is divided by the voids, and not only the heat is not uniformly transferred to the entire surface of the joint surface of the material to be joined, but also the heat transfer efficiency is lowered.

Since the heat-generating material has a low-melting-point metal material on the contact surface with the material to be bonded, that is, the surface thereof, the low-melting-point metal material melts due to the heat of reaction to fill the voids at the contact interface, and the material to be bonded and the heat-generating material Can adhere to each other and transfer the heat of reaction of the heating material uniformly and efficiently to the entire surface of the joint surface.
Therefore, the joint surface of the material to be joined is uniformly and sufficiently melted, and it is possible to form a uniform and excellent bonding interface.

The low melting point metal material is preferably laminated in contact with the thermite reaction material.
When the low melting point metal material is in contact with the thermite reaction material, the low melting point metal material melts early due to the reaction heat of the first thermite reaction, so that the reaction heat of the self-burning synthesis reaction is efficiently used as the material to be bonded. I can tell.

The metal material constituting the low melting point metal material is not particularly limited as long as it forms a reaction layer with the metal material of the material to be joined and melts earlier than the material to be joined, and both of the materials to be joined are not particularly limited. A metal material having a melting point equal to or lower than the melting point can be used.

That is, when the materials to be joined are of the same type and have the same melting point, the melting point of the low melting point metal material may be equal to or lower than the melting point of the material to be joined, and the materials to be joined are different materials and have a melting point. The melting point of the low melting point metal material in different cases may be equal to or lower than the melting point of the material to be joined, which has a lower melting point.

Specific examples thereof include an alloy containing the same metal as the material to be joined having a lower melting point, a metal forming an intermetallic compound with the metal material of the material to be joined, or an alloy thereof.

As the shape of the low melting point metal material, a mesh-like sheet, a green compact, a foil or the like can be used, but a mesh-like sheet is preferable.
The low melting point metal material of the mesh-like sheet forms a gap between it and the material to be bonded, and when the thermite reaction propagates, it divides the heat transfer path of the reaction heat to the material to be bonded, and the heat of reaction is transferred to the material to be bonded. Prevents being deprived and stopping the propagation of the thermite reaction. In addition, the volume heat capacity is smaller than that of a foil having the same thickness, and after the thermite reaction has propagated, it melts at an early stage to promote heat exchange between the reaction material and the material to be joined.

In the present invention, the mesh-like sheet means a mesh-like sheet in which metal wires formed of a low melting point metal are regularly knitted, and a sheet in which a plurality of slits and holes are regularly or irregularly formed. do.

The thickness of the low melting point metal material may be such that the voids at the contact interface with the material to be joined may be filled by melting, and although it depends on the surface roughness of the material to be joined, it is preferably 100 μm or more and 700 μm or less. When the thickness of the low melting point metal material exceeds 700 μm, the energy required for melting the low melting point metal material increases, and a large amount of reaction material is required.

The thermite reaction material contains a metal oxide powder and a metal aluminum powder, and if necessary, contains a combustion rate adjusting material such as a thermite reaction product that reduces the apparent reaction rate without being involved in the thermite reaction. can do.

As the metal oxide, metal oxides conventionally used for thermite reaction can be used, and among them, copper oxide (CuO), manganese oxide (MnO ₂ ), tin oxide (SnO ₂ ), and iron oxide. (Fe ₂ O ₃ ) has a low activation energy and can cause a thermite reaction with a low energy.

The mixing ratio of the metal oxide and the metal aluminum (metal oxide / metal aluminum) is preferably a chemical quantitative ratio.

The average particle size of the metal oxide is preferably 0.1 μm or more and 10 μm or less, and more preferably 0.5 μm or more and 3 μm or less.

The average particle size of the metallic aluminum is preferably 1 μm or more and 50 μm or less, and more preferably 5 μm or more and 20 μm or less.
If it is less than 1 μm, combustion is severe and control becomes difficult, and if it exceeds 50 μm, the reaction is likely to be interrupted and the reactant may remain.

The self-combustion synthetic reaction material contains two or more kinds of inorganic substances that spontaneously generate a compound by an exothermic reaction.
As the combination of the above-mentioned inorganic substances, it is sufficient that a self-combustion synthesis reaction occurs, and two or more conventionally known inorganic substances that cause a self-combustion synthesis reaction can be used in combination.

Among them, a self-combustion synthetic reaction material that combines boron (B) and titanium (Ti) or zirconium (Zr), or a self-combustion synthesis that combines carbon (C) and titanium (Ti) or zirconium (Zr). The reaction material has a low activation energy, can easily initiate a self-combustion synthesis reaction, and can be preferably used.

The mixing ratio (Ti or Zr / B or C) of the above boron or carbon and titanium or zirconium is preferably a chemical quantitative ratio, and is 0.5 to 1.0 (Mol) depending on the combination of inorganic substances. Ratio) is preferable.

The self-combustion synthetic reaction material may contain a filler, if necessary.
Even when the reaction product of the self-combustion synthetic reaction material tends to have voids and has poor ductility, the inclusion of the filler can prevent the formation of voids and impart ductility.

As the filler, a metal material of the same type as the metal material of the material to be joined can be used, and the content of the filler in the self-burning synthetic reaction material is preferably 10% by mass or more and 30% by mass. .. By including the filler in the above range, the generation of voids can be prevented and the bonding strength is improved.

The self-combustion synthetic reaction material does not necessarily have to be a mixture of powders, and may be laminated by plating, spattering, or the like.

The content ratio of the self-burning synthetic reaction material to the thermite reaction material (self-burning synthetic reaction material / thermite reaction material) of the exothermic material is preferably 50/50 to 30/70 (mass%).

The exothermic material is a laminate obtained by laminating a thermite reaction material in which a predetermined amount of metal oxide powder and metal aluminum powder are mixed, and a self-burning synthetic reaction material in which a predetermined amount of two or more kinds of inorganic substances are similarly mixed. It can be produced by adding a low melting point metal material. Further, the laminate can be produced by press molding, cold spraying, solidifying the slurry, or the like.

In the joining method of the present invention, the exothermic material is inserted between the exothermic materials, pressurized at, for example, 5 to 20 MPa to bring the exothermic material into close contact with the exothermic material, and the exothermic material is ignited to start the reaction. , The materials to be joined can be joined by the reaction heat obtained by the controlled reaction.

As an ignition device for igniting the exothermic material, a condenser discharge, a heating wire, an ignition ball, or the like can be used.

The joined body joined by the above-mentioned joining method of the present invention contains the reaction product of the Thermit reaction material, the reaction product of the self-combustion synthetic reaction material, and the low melting point metal at the interface between the materials to be joined, and is uniform. It has a high bonding strength because it forms a bonding interface with high adhesion.

The reaction products of the Thermit reactants, the reaction products of the self-burning synthetic reactants, and the low melting point metals produced at the junction interface are described by electron probe microanalyzer (EPMA) energy dispersion X-ray analysis (EDS, EDX). It can be observed by wavelength dispersive X-ray spectroscopy (WDX) or the like.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to the following Examples.

[Example 1]
1.26 g of titanium powder having an average particle size of 38 μm and 0.57 g of boron powder having an average particle size of 40 μm were mixed in an agate mortar for 10 minutes to prepare a self-burning synthetic reaction material powder.

Similarly, 0.22 g of metallic aluminum powder having an average particle size of 20 μm and 0.95 g of copper oxide (CuO) powder having an average particle size of 1 μm were mixed in a Menou mortar for 10 minutes to prepare a thermite reaction material powder.

Self-burning synthetic reaction material powder, thermite reaction material powder, self-burning synthetic reaction material powder so that the content ratio of self-burning synthetic reaction material powder and thermite reaction material powder is 30.56 / 38.88 / 30.56. In this order, the powder is put into a metal mold with a hole of φ10 mm, and the powder is compressed with a pressing force of 1.5 GPa using a press machine to form a disk-shaped three-layer with a diameter of 10 mm and a thickness of about 1 mm. A laminated body of the structure was molded.

A mesh-shaped aluminum alloy sheet (melting point 650 ° C., wire diameter: 100 mesh, space ratio: 32.141%, opening: 0.144 mm, thickness: 0.22 mm) is applied to both sides of the laminate one by one. , The laminated body was sandwiched between aluminum alloy sheets to form a heat generating material.

The exothermic material is sandwiched from both sides of the aluminum alloy (A6061, t2.0: melting point 652 ° C.), which is the material to be bonded, and is pressurized at 5 MPa to bring the exothermic material and the material to be bonded into close contact with each other. , The energy for starting the bonding was applied to obtain a bonded body in which the aluminum alloys were bonded to each other.

At the bonding interface of this bonded body, there were few unreacted self-burning synthetic reaction materials and unreacted thermite reaction materials, and a good adhesion interface was obtained.
The joint strength of this joint was 9 MPa in tensile shear strength.
FIG. 2 shows a cross-sectional SEM image of the joining interface of the joining body of Example 1.

[Example 2]
The aluminum alloy and the steel plate are used in the same manner as in Example 1 except that the heat generating material is sandwiched between an aluminum alloy (A6061, t2.0: melting point 652 ° C.) and a steel plate (mild steel plate, t0.8: melting point 1527 ° C.). An alloy was obtained.

At the bonding interface of this bonded body, there were few unreacted self-burning synthetic reaction materials and unreacted thermite reaction materials, a good adhesion interface was obtained, and the joint strength was high.

[Example 3]
1.62 g of zirconium powder having an average particle size of 38 μm and 0.38 g of boron powder having an average particle size of 40 μm were mixed in an agate mortar for 10 minutes to prepare a self-burning synthetic reaction material powder.

Similarly, 0.29 g of metallic aluminum powder having an average particle size of 10 μm and 0.70 g of manganese oxide (MnO ₂ ) powder having an average particle size of 1 μm were mixed in a Menou mortar for 10 minutes to prepare a thermite reaction material powder.

Thermite reaction material powder, self-burning synthetic reaction material powder, and thermite reaction material powder are in this order so that the content ratio of the self-burning synthetic reaction material powder and the thermite reaction material powder is 33.47 / 33.06 / 33.47. , Put into a metal mold with a hole of φ10 mm, and compress the powder with a pressing force of 1.5 GPa using a press machine to form a disk-shaped three-layer structure with a diameter of 10 mm and a thickness of about 1 mm. The laminate was molded.

A mesh-shaped aluminum alloy sheet (melting point 650 ° C., wire diameter: 100 mesh, space ratio: 32.141%, opening: 0.144 mm, thickness: 0.22 mm) is provided on both sides of the laminate. A bonded body of aluminum alloys was obtained in the same manner as in Example 1 except that the heat-generating material was used.

At the bonding interface of this bonded body, there were few unreacted self-burning synthetic reaction materials and unreacted thermite reaction materials, a good adhesion interface was obtained, and the joint strength was high.

[Example 4]
The aluminum alloy and the steel plate are used in the same manner as in Example 3 except that the heat generating material is sandwiched between an aluminum alloy (A6061, t2.0: melting point 652 ° C.) and a steel plate (mild steel plate, t0.8: melting point 1527 ° C.). An alloy was obtained.

At the bonding interface of this bonded body, there were few unreacted self-burning synthetic reaction materials and unreacted thermite reaction materials, a good adhesion interface was obtained, and the joint strength was high.

[Example 5]
0.99 g of titanium powder having an average particle size of 38 μm and 0.25 g of carbon powder having an average particle size of 40 μm were mixed in an agate mortar for 10 minutes to prepare a self-burning synthetic reaction material powder.

Similarly, 0.34 g of metallic aluminum powder having an average particle size of 10 μm and 1.42 g of tin oxide (SnO ₂ ) powder having an average particle size of 1 μm were mixed in a Menou mortar for 10 minutes to prepare a thermite reaction material powder.

Thermite reaction material powder, self-burning synthetic reaction material powder, and thermite reaction material powder are in this order so that the content ratio of the self-burning synthetic reaction material powder and the thermite reaction material powder is 20.72 / 58.56 / 20.72. , Put into a metal mold with a hole of φ10 mm, and compress the powder with a pressing force of 1.5 GPa using a press machine to form a disk-shaped three-layer structure with a diameter of 10 mm and a thickness of about 1 mm. The laminate was molded.

A mesh-shaped aluminum alloy sheet (melting point 650 ° C., wire diameter: 100 mesh, space ratio: 32.141%, opening: 0.144 mm, thickness: 0.22 mm) is provided on both sides of the laminate. A bonded body of aluminum alloys was obtained in the same manner as in Example 1 except that the heat-generating material was used.

At the bonding interface of this bonded body, there were few unreacted self-burning synthetic reaction materials and unreacted thermite reaction materials, a good adhesion interface was obtained, and the joint strength was high.

[Example 6]
The aluminum alloy and the steel plate are used in the same manner as in Example 5 except that the heat generating material is sandwiched between an aluminum alloy (A6061, t2.0: melting point 652 ° C.) and a steel plate (mild steel plate, t0.8: melting point 1527 ° C.). An alloy was obtained.

At the bonding interface of this bonded body, there were few unreacted self-burning synthetic reaction materials and unreacted thermite reaction materials, a good adhesion interface was obtained, and the joint strength was high.

[Example 7]
2.02 g of zirconium powder having an average particle size of 38 μm and 0.27 g of carbon powder having an average particle size of 40 μm were mixed in an agate mortar for 10 minutes to prepare a self-burning synthetic reaction material powder.

Similarly, 0.18 g of metallic aluminum powder having an average particle size of 10 μm and 0.53 g of iron oxide (Fe ₂ O ₃ ) powder having an average particle size of 1 μm were mixed in a Menou dairy pot for 10 minutes to prepare a thermit reaction material powder.

Thermite reaction material powder, self-burning synthetic reaction material powder, and thermite reaction material powder are in this order so that the content ratio of the self-burning synthetic reaction material powder and the thermite reaction material powder is 38.09 / 23.82 / 38.09. , Put into a metal mold with a hole of φ10 mm, and compress the powder with a pressing force of 1.5 GPa using a press machine to form a disk-shaped three-layer structure with a diameter of 10 mm and a thickness of about 1 mm. The laminate was molded.

A mesh-shaped aluminum alloy sheet (melting point 650 ° C., wire diameter: 100 mesh, space ratio: 32.141%, opening: 0.144 mm, thickness: 0.22 mm) is provided on both sides of the laminate. A bonded body of aluminum alloys was obtained in the same manner as in Example 1 except that the heat-generating material was used.

At the bonding interface of this bonded body, there were few unreacted self-burning synthetic reaction materials and unreacted thermite reaction materials, a good adhesion interface was obtained, and the joint strength was high.

[Example 8]
The aluminum alloy and the steel plate are used in the same manner as in Example 7 except that the heat generating material is sandwiched between an aluminum alloy (A6061, t2.0: melting point 652 ° C.) and a steel plate (mild steel plate, t0.8: melting point 1527 ° C.). An alloy was obtained.

At the bonding interface of this bonded body, there were few unreacted self-burning synthetic reaction materials and unreacted thermite reaction materials, a good adhesion interface was obtained, and the joint strength was high.

[Example 9]
A bonded body of aluminum alloys was obtained in the same manner as in Example 1 except that 20% by mass of aluminum particles having an average particle size of 20 μm were added to the self-burning synthetic reaction material powder of Example 1.
The tensile shear strength of this joint was 21 MPa, and it had a high joint strength.
FIG. 3 shows a cross-sectional SEM image of the joining interface of the joining body of Example 9.

[Example 10]
A bonded body of aluminum alloys was obtained in the same manner as in Example 1 except that 40% by mass of aluminum particles having an average particle size of 20 μm were added to the self-burning synthetic reaction material powder of Example 1.
The tensile shear strength of this joint had a joint strength of 13 MPa.
FIG. 4 shows a cross-sectional SEM image of the joining interface of the joining body of Example 10.

[Comparative Example 1]
A bonded body was obtained in the same manner as in Example 1 except that the mesh-shaped aluminum alloy sheet was not applied to the laminated body.

Voids were formed at the bonding interface of this bonded body, and unreacted Ti-B self-burning synthetic reaction material and Al-CuO thermite reaction material remained. From this, it was confirmed that the effect of using the exothermic material provided with the low melting point metal at the bonding interface of the present invention was confirmed.

[Comparative Example 2]
A bonded body was obtained in the same manner as in Example 1 except that an exothermic material having a mesh-shaped aluminum alloy sheet added to the green compact of the self-burning synthetic reaction material powder was used without using the thermite reaction material powder.

The bonding interface of this bonded body was a non-uniform bonding interface in which a low melting point metal and a non-melted region of an Al alloy as a material to be bonded were mixed. From this, the effect of using the exothermic material provided with the self-burning synthetic reaction material and the redox reaction material of the present invention was confirmed.

[Comparative Example 3]
A bonded body was obtained in the same manner as in Example 1 except that an exothermic material having a mesh-shaped aluminum alloy sheet added to the green compact of the thermite reaction material powder was used without using the self-burning synthetic reaction material powder.

The bonding interface of this bonded body was a non-uniform bonding interface in which voids were present. It is considered that this is because the reaction of the thermite reactant is steep and melting and solidification occur in a short time. From this, the effect of using the exothermic material provided with the self-burning synthetic reaction material and the redox reaction material of the present invention was confirmed.

[Comparative Example 4]
A bonded body was obtained in the same manner as in Comparative Example 2 except that the ingot powder of the self-burning synthetic reaction material powder was used without using the mesh-shaped aluminum alloy sheet and the thermite reaction material powder.

The bonding interface of this bonded body was a non-uniform bonding interface in which a non-melted region of the Al alloy as the material to be bonded was present and an unreacted Ti-B self-burning synthetic reaction material remained.

[Comparative Example 5]
A bonded body was obtained in the same manner as in Comparative Example 3 except that the powder of thermite reaction material powder was used without using the mesh-shaped aluminum alloy sheet and the self-burning synthetic reaction material powder.

The bonding interface of this bonded body was a non-uniform bonding interface in which voids were present and an unreacted Al—CuO thermite reactant remained.

1 Exothermic material 2 Low melting point metal material 3 Thermite reaction material 4 Self-burning synthetic reaction material

Claims (4)

It is a joining method in which the exothermic material between the materials to be joined is generated to generate heat and the above-mentioned materials to be joined are joined to each other.
The exothermic material contains a self-burning synthetic reaction material and a thermite reaction material, and has a low melting point metal material on a contact surface with at least one of the materials to be joined.
The melting point of the low melting point metal material is equal to or lower than the melting point of both bonded materials to be bonded .
A joining method characterized in that the self-burning synthetic reaction material and the thermite reaction material are powders . The joining method according to claim 1, wherein the shape of the low melting point metal material is a mesh-like sheet. The thermite reactant is composed of at least one metal oxide selected from the group consisting of copper oxide (CuO), manganese oxide (MnO ₂ ), tin oxide (SnO ₂ ), and iron oxide (Fe ₂ O ₃ ). The joining method according to claim 1 or 2 , wherein the bonding method comprises aluminum (Al). The self-burning synthetic reaction material is characterized by a combination of boron (B) and titanium (Ti) or zirconium (Zr), or a combination of carbon (C) and titanium (Ti) or zirconium (Zr). The joining method according to any one of claims 1 to 3 .

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