JPH09108886A - Joint structure for members - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a joint structure in which the penetration of a joint surface metal is obviated and the joint strains between two members varying in the coeffts. of expansion are decreased by metallurgically coupling the two members by holding a melt phase of an alloy contg. an active metal between these members. SOLUTION: The members of the joint structure of the metal-metal, the metal-ceramics are joined across the melt phase of the M-X (X is the active metal) alloy. The joint surface of the metallic member consists of the metal Y which does not form the alloy with the metal M or a metallic material formed with an oxidized film or nitrided film which does not cause the reaction of the molten metal M. Y does not melt into the metal M in the case of the metal Y. The penetration of the metallic component into the metal M does not arise in the case of the metallic material formed with the oxidized film and the nitrided film. The active metal X added into the metal M is diffused into the metal Y or the oxidized film and nitrided film, by which the melt M-X alloy and the metal Y or the melt M-X allay and the oxidized film and nitrided film are metallurgically coupled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joining structure of members, and more particularly to a joining structure capable of reducing a joining strain between two members having different expansion coefficients.

[0002]

2. Description of the Related Art In metal-metal or metal-ceramic joining, when joining members having different thermal expansion coefficients, a soft metal is often used as a brazing material. For example, a low melting point metal such as In, Sn, Zn, Pb, Cd, A
Noble metals such as g, Au, Pt, and Pd are generally soft metals, and when they are joined together, thermal strain caused by a difference in thermal expansion coefficient is relaxed by plastic deformation or elastic deformation of these metals. In this case, the problem is that the joining surface metal of the joining member is melted into the brazing filler metal. As a result, the brazing filler metal is hardened, the deformation resistance of the brazing filler metal increases, and the residual stress in the joint increases. If one of the members is ceramic, in the worst case the ceramic may be destroyed. Since this penetration is a metallurgically unavoidable phenomenon, it has been conventionally considered how to reduce the residual stress after allowing the deformation resistance to increase due to the penetration. The most common method is to insert an intermediate layer with an intermediate coefficient of expansion. The insertion of the intermediate layer merely reduces the difference in thermal expansion between the adjacent members to reduce the residual stress, and the current situation is that no fundamental solution has been made.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a new joining structure capable of completely or minimally melting the joining surface metal. It is a thing.

[0004]

Means for Solving the Problems The present inventor has made intensive studies on the above problems and obtained the following findings. That is, in order to prevent the melting at the joint, if the brazing filler metal and the joint metal do not react with each other, or if a metal that does not form an alloy is used, the joint metal does not melt into the molten brazing filler metal (but On the other hand, the present invention was conceived, focusing on the fact that joining does not occur). That is, 1. A structure in which two members, at least one of which has a joining surface made of a metal, is metallurgically joined with a melt phase of an alloy of M-X (X being an active metal) sandwiched therebetween, and the joining portion metal The surface is made of metal Y which does not react with the melt of the metal M and exists in a solid state at the melt temperature at the time of joining the MX alloy, and the active metal X diffuses into the metal Y. A joining structure of members, wherein the alloy M-X and the metal Y are metallurgically joined. 2. The metal M is In, Sn, Au, Ag, Cu, A
An alloy mainly composed of one or more metals selected from L, Pd, Zn, Pb and Cd, in which the metal Y is a metal selected from Cr, Mo and W. The joining structure described. 3. The joining structure according to 1 or 2, wherein the metallurgical joining is with brazing. 4. A structure in which two members, at least one of which is made of metal, are metallurgically bonded with a melt phase of an alloy M-X (X is an active metal) sandwiched therebetween, and at least the bonding of the metal members The surface is one or more metals selected from (Fe, Ni, Co), and (Cr, AL, S
An alloy containing one or more metals selected from i) as the main component, and Cr is 10% or more, A
L is 1% or more, and Si is 1% or more, and an oxide film of Cr, AL, or Si contained as a component is formed on the surface of the alloy. Junction structure. 5. The metal M is In, Sn, Au, Ag, Cu, A
5. The joint structure according to 4, which is an alloy containing one or more metals selected from L, Pd, Zn, Pb, and Cd as a main component. 6. Two members, at least one of which is made of metal, are metallurgically bonded with a melt of an alloy M-X (X is an active metal) sandwiched therebetween, and the metal surface of the bonded portion is nitrided. A joining structure of members characterized by the following. 7. The junction structure according to any one of 1 to 6, wherein the active metal X is a metal selected from Ti, Zr, Nb, and Ta.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is a joining structure of members in which at least one member is made of metal. That is, it is a metal-metal or metal-ceramic bonding structure. These members are joined with a melt phase of an alloy of M-X (X is an active metal) interposed therebetween. That is, they are metallurgically joined by the molten MX alloy. At this time, the joint surface of the metal member is made of a metal Y that does not form an alloy with the metal M or a metal material that has an oxide film or a nitride film that does not react with the molten metal M. In the case of the metal Y, Y does not melt into the melted metal M, and in the case of a metal material having an oxide film or a nitride film, this metal component does not melt into the metal M. However, on the other hand, they are not metallurgically bonded. Here, the active metal X added to M is metal Y
Alternatively, the melt M is formed by diffusing into an oxide film or a nitride film.
The -X alloy and the metal Y or the melt MX alloy and the oxide film or the nitride film are metallurgically bonded.

It is sufficient to add 0.1 to several% of the active metal X to be added. It is preferably 0.1 to 5%, most preferably 0.5 to 2%. Excessive addition (10% or more) hardens the MX alloy and is not preferred.

The metal Y does not necessarily have to be Y for the entire member because at least the surface of the member must be Y.
A different material may be coated with metal Y. Effective means of coating are plating, thermal spraying, sputtering.

The metal Y is Cr, Mo, W or an alloy thereof, and the metal M is In, SnZn, Pb, Cd,
It is an alloy whose main component is one or more metals selected from AL, Au, Ag, Cu and Pd.

In a member having an oxide film formed on its surface, the component composition of the surface is one or more metals selected from (Fe, Ni, Co), and (Cr, A
L, Si) is an alloy mainly composed of one or more metals selected from the group consisting of (L, Si) and Cr AL, Si is present alone, the Cr content is 10% or more, and the AL content is AL. Is preferably 1% or more, and Si is preferably 1% or more. When Cr and AL coexist, and Cr and Si coexist, Cr is preferably 5% or more and AL and Si are preferably 0.5% or more. When AL and Si coexist, the sum of AL and Si is 1
% Or more is preferable. When Cr, AL and Si coexist,
It is preferable that Cr is 5% or more and the sum of AL and Si is 0.5% or more. Those having these component ranges are dense on the surface, have strong adhesion, and can form a stable oxide film. The upper limit of these elements is not particularly limited to Cr, but considering economic efficiency, it is up to about 40%, about 5% for AL, and about 10% for Si. If it exceeds the upper limit, melting becomes difficult. The member may be wholly integrally formed of the materials of the above-mentioned components, or may have only the surface made of this component. That is, the surface of this component may be coated. The coating is not particularly limited, and any method can be applied as long as the coating of the present component can be formed. Among them, thermal spraying is particularly effective. When the material of this component is oxidized and annealed at a high temperature of 800 ° C. or higher, a denser and thicker oxide film is formed. Alternatively, the oxide film may be formed by coating the surface of the joining member metal with ceramic. That is, the ceramic may be coated by means such as thermal spraying, sputtering, PVD, CVD, or sol-gel method. Sputtering, PVD, C
When the VD method is adopted, nitride and carbide coatings can be formed, and both are effective for the present invention.

There is no particular limitation on the composition of the member having the nitride film formed on its surface, but a steel material called nitrided steel is preferable.

Active metals include Ti, Zr, Nb, Ta and V.
One or two or more of these may be selected and used as appropriate.

[0012]

【Example】

Example 1 Member 1: Alumina plate (φ200 mm × 10 mm thickness) Member 2: Carbon steel plate (φ200 mm × 20 mm thickness) Brazing material: In-1% Ti (100 micron) Wax between members 1 and 2 Sandwich the foil of the material, in vacuum (1 x 10
^-5 torr) Heated to 800 ° C and brazed. Cracks occurred on the alumina plate. Brazing material (In-1% T
A large amount of iron was dissolved in i). Next, the carbon steel plate of the member 2 was plated with nickel of 5 microns, and chromium was plated with 10 microns on the plate.
(100 micron) was sandwiched and brazed under the same conditions. Alumina could be joined without cracking. As a result of observing the microstructure, dissolution of chromium into In was not recognized. Further, in the component analysis as well, the dissolution of chromium into the brazing material was not observed. By coating chrome,
It was confirmed that the steel was prevented from melting into In and was effective in preventing cracking.

Example 2 Member 1: Mo plate (φ180 mm × 5 mm thickness) Member 2: Pure copper plate (φ180 mm × 10 mm thickness) Brazing material: Sn-1% Zr (80 μm) Between members 1 and 2 Sandwich a foil of brazing material in a vacuum (1 x 10
^-5 torr) Heated to 850 ° C and brazed. The joining material was bowed in the direction of pure copper. The amount of warpage is 1000
Micron. A large amount of copper was dissolved in the brazing material (Sn-1% Zr). Next, the pure copper plate of member 2 is applied with 10
0 micron sprayed with tungsten, Sn-1% Zr
(80 microns) were sandwiched and brazed under the same conditions. The amount of warpage was 300 microns. As a result of observing the microstructure, tungsten did not dissolve into Sn.
In addition, in the component analysis, no dissolution of tungsten into the brazing material was observed. It was confirmed that by coating with tungsten, the dissolution of copper in Sn was prevented and the deformation was significantly prevented.

Example 3 Member 1: Alumina plate (φ80 mm × 5 mm thickness) Member 2: Fe-3% C-3% AL cast iron plate (φ80 mm)
Comparative material 1: Fe-3% C cast iron plate (φ80 mm × 10 m)
Comparative thickness 2: Fe-3% C cast iron plate (φ80 mm × 10 m)
(m thickness), which was sprayed with Ni-10% Cr-3% AL-1% Y alloy by 100 microns. Brazing material: AL-0.5% Ti (120 micron) The member 2 was heated at 900 ° C. in the atmosphere for 2 hours to be oxidized. A brazing material foil was sandwiched between the members 1 and 2 and between the member 1 and the comparative materials 1 and 2, respectively, and heated at 850 ° C. in vacuum (1 × 10 ⁻⁵ torr) and brazed. In members 1 and 2, alumina could be joined without cracking. In the component analysis, the dissolution of cast iron into the brazing material (AL-0.5% Ti) was not recognized. On the other hand, the alumina cracked in the member 1 and the comparative material 1. In this combination, aluminum and cast iron were alloyed to form a hard and brittle phase. On the other hand, in the member 1 and the comparative material 2, the alumina could be joined without cracking. In the component analysis, no penetration of the sprayed layer into the brazing material (AL-0.5% Ti) was observed. The oxide film on the surface of the sprayed layer prevented the penetration. It was confirmed that the oxide film on the surface of the member could prevent the formation of the alloy layer and prevent cracking.

Example 4 Member 1: Alumina plate (φ100 mm × 5 mm thickness) Member 2: Nitrided Fe-0.1% C-2% Cr steel plate (φ100 mm × 10 mm thickness) Comparative material: Fe -0.1% C-2% Cr steel plate (untreated)
(Φ100 mm × 10 mm thickness) Brazing material: Sn-0.5% Ti (100 μm) A brazing material foil is sandwiched between the members 1 and 2 and between the member 1 and the comparative material, and in vacuum (1 × 10 ^{− 5} Torr) 850 ° C
Heated and brazed. In members 1 and 2, alumina could be joined without cracking. In the component analysis, the brazing material (Sn-
No dissolution of iron into 0.5% Ti) was observed.
On the other hand, alumina cracked in the member 1 and the comparative material. In this combination, iron was dissolved in Sn to form a hard and brittle phase. It was confirmed that the nitride film on the surface of the member can prevent the formation of the alloy layer and prevent cracking.

Example 5 Member 1: Silicon Carbide Plate (φ80 mm × 2 mm Thickness) Member 2: Fe-42% Ni Steel Plate (φ80 mm × 10 m)
m thickness) (High-purity alumina sprayed on the bonding surface to 30 microns) Comparative material 1: Fe-42% Ni steel plate (untreated) (φ80
mm × 10 mm thickness) Comparative material 2: Fe-42% Ni steel plate (φ80 mm × 10 m) with TiC 0.5 μm and PVD coated on the joint surface
m thickness) Brazing material: Sn-5% Ag-1% Zr (100 microns) A brazing material foil is sandwiched between the members 1 and 2 and between the member 1 and the comparative materials 1 and 2, respectively, and in vacuum (1 x ^10-5 torr) 8
It was heated to 50 ° C and brazed. In members 1 and 2, the ceramic could be joined without cracking. On the other hand, member 1 and comparative material 1
Then the ceramic plate broke. In this combination, the brazing material and 42Ni steel were alloyed to form a hard and brittle phase. On the other hand, in the member 1 and the comparative material 2, the ceramics could be joined without cracking. In component analysis, 42N for brazing material
No penetration of i-steel was observed. The PVD coating of TiC prevented penetration. It was confirmed that the ceramic film on the surface of the member can prevent the formation of the alloy layer and prevent cracking.

[0017]

As described above in detail, the present invention has a feature that cracking and deformation of the joining member can be minimized, and exerts great power in joining large-sized members made of metal or ceramic material.

Claims (7)

[Claims] 1. A structure in which two members, at least one of which has a bonding surface made of metal, are metallurgically bonded with a melt phase of an alloy of MX (X is an active metal) interposed therebetween. , The joint metal surface does not react with the melt of the metal M, and the MX
Metal Y that exists in the solid state at the melt temperature when joining alloys
And a metal-metallurgically-bonded alloy M-X and metal Y by diffusing the active metal X into the metal Y. 2. The metal M is In, Sn, Au, Ag, C.
An alloy mainly composed of one or more metals selected from u, AL, Pd, Zn, Pb and Cd, and a metal Y is a metal selected from Cr, Mo and W. The joint structure according to claim 1. 3. The joining structure according to claim 1, wherein the metallurgical joining is brazing. 4. A structure in which two members, at least one of which is made of metal, are metallurgically joined with a melt of an alloy of MX (where X is an active metal) sandwiched between them. At least the joint surface of the member is composed of one or more metals selected from (Fe, Ni, Co), and (Cr, A
L, Si) is an alloy mainly composed of one or more metals selected from among L, Si), and is 10% or more for Cr, 1% or more for AL, and 1 for Si. % Or more of an alloy, and an oxide film of Cr, AL, or Si contained as a component is formed on the surface of the alloy, the joining structure of members. 5. The metal M is In, Sn, Au, Ag, C.
The joint structure according to claim 4, which is an alloy containing one or more metals selected from u, AL, Pd, Zn, Pb, and Cd as a main component. 6. A structure in which two members, at least one of which is made of metal, are metallurgically bonded with a melt phase of an alloy of MX (X is an active metal) sandwiched between them. A joining structure of members, wherein the metal surface of the part is nitrided. 7. The active metal X is Ti, Zr, Nb, T.
The joining structure according to any one of claims 1 to 6, which is a metal selected from a.