JPH0526599B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to the improvement of a solder for brazing ceramics and metal, and more specifically, to prevent damage due to compressive stress being applied to ceramics during brazing and cooling to room temperature. Therefore, it is related to clad solder which relieves thermal stress. (Prior Art) In recent years, various ceramic materials have begun to be used in a wide variety of fields because they exhibit properties that metals do not have, such as excellent heat resistance and wear resistance. Although some parts are made from ceramic alone, many require the use of the characteristics of ceramics and metals. Therefore, bonding between ceramics and metal is required. Ceramics and metals have different atomic bonds, and cannot be directly bonded using general brazing filler metals. A brazing filler metal containing an active metal is known as a brazing filler metal that provides good bonding. As active metals, Ti and Zr are effective for joining ceramics and metals, but Ti,
Zr alone has a high melting point (Ti 1720℃, Zr 1860℃)
Therefore, it is usually used by alloying it with Cu, Ni, etc. to lower its melting point. (Problems to be Solved by the Invention) By the way, ceramics and metal can be brazed using a brazing filler metal made by alloying Ti, Zr, etc. with Cu, Ni, etc., but since the brazing temperature is high,
Ceramics had the disadvantage of cracking due to stress. The cause of cracks is due to the difference in thermal expansion between ceramics and metals. In particular, non-oxide ceramics such as SiC and Si ₃ N ₄ and metals such as stainless steel, Cu, and Fe are extremely Since the difference in thermal expansion is large, this is compared to the above-mentioned Ti,
When brazing with a brazing filler metal made by alloying Zr, etc. with Cu, Ni, etc., the stainless steel expands significantly compared to the expansion of the ceramics during brazing, and when this is cooled to room temperature, the ceramics shrink. In comparison, stainless steel shrinks more, and the stress caused by this difference can cause cracks. SUMMARY OF THE INVENTION Therefore, the present invention provides a clad solder containing an active metal that can relieve stress and ensure strong bonding after brazing ceramics and metals. (Means for Solving the Problems) One of the clad solders of the present invention for solving the above problems uses a metal or alloy with a small coefficient of thermal expansion as an intermediate material, and contains 0.5 to 8 wt% of active metal on one side. The Ag solder contained therein is characterized in that an Ag solder having a melting point close to that of the Ag solder is applied on the other side, and the liquidus temperature is 850° C. or less. Another method of the clad solder of the present invention is to have up to three layers of a metal or alloy with a small coefficient of thermal expansion as an intermediate material, and 0.5 to 8 wt of active metal between the intermediate materials.
Ag solder containing 0.5 to 8 wt % of active metal is inserted on one outermost surface, and Ag solder containing 0.5 to 8 wt % of active metal is inserted on the other outermost surface.
It is characterized by being covered with Ag wax that has a melting point close to that of Ag wax containing 8wt%. Still another one of the clad solders of the present invention has two or three layers of intermediate material, of which one or two layers from the outside are made of a metal or alloy with a small coefficient of thermal expansion,
The remaining one or two layers are either Cu, Cu alloy, Ag, Ag alloy, Ni, or Ni alloy, and the intermediate material between these two or three layers is Ag containing 0.5 to 8 wt% of active metal. Ag wax with a melting point close to the wax is inserted,
0.5 to 8 wt% of active metal is contained on the outermost surface of the intermediate material side of the metal or alloy with a small coefficient of thermal expansion.
Ag solder is placed on the other outermost surface of the outermost surface.
It is characterized by being covered with Ag wax, which has a melting point close to that of Ag wax. In one of the clad solders of the present invention, a metal or alloy with a small thermal expansion coefficient is used as an intermediate material because it reduces the difference in thermal expansion with ceramics and relieves stress after brazing. This is because good bonding between ceramics and metal can be achieved. In addition, the reason for applying Ag solder containing 0.5 to 8 wt% of active metals on one side of the intermediate material is to improve workability.
In order to increase strength, active metal content of less than 0.5wt%
Ag wax has poor wettability to ceramics,
In addition, the strength is insufficient and the active metal content exceeds 8wt%.
With Ag brazing, the workability of the brazing metal is poor, and Cu-
This is because segregation of the Ti alloy occurs, and in addition, the melting point of the solder increases, and the solder loses its toughness during brazing, causing cracks in ceramics. Furthermore, the other side of the intermediate material contains the active metal in a range of 0.5 to 0.
The reason why Ag solder having a melting point close to that of Ag solder containing 8 wt% is used is that it has better wettability to the metal and improves joint strength than Ag solder containing active metals. The reason why the liquidus temperature was set to 850°C or less was to minimize the stress applied to the ceramics after brazing. The reason why the intermediate material is made of two or three layers in another method of the clad solder of the present invention is that the bond between the ceramic and the metal can be made even better, and the bonding effect cannot be further improved by using four or more layers. This is because the cost will only increase. Furthermore, the reason why Ag solder containing 0.5 to 8 wt% of active metal and having a melting point close to that of Ag solder is inserted between the intermediate materials is to alleviate the stress between the intermediate materials and the ceramics even if the intermediate materials have two or three layers. . The material applied to the outermost surfaces is limited for the same reasons as in the case of the clad solder described above. In yet another Clad solder of the present invention, the intermediate material is two or three layers, and the active metal is 0.5
The reason why one or two layers on the brazing side of Ag containing ~8wt% is made of a metal or alloy with a small coefficient of thermal expansion is to reduce the difference in thermal expansion with ceramics and alleviate the stress applied to the ceramics after brazing. be. In addition, the other one or two layers of the intermediate material are Cu, Cu.
The reason for selecting Ag, Ag alloy, Ni, or Ni alloy is that stress relaxation can be achieved to some extent by the intermediate material of the first layer, so these metals can also suffice. Metals or alloys with a small coefficient of thermal expansion as intermediate materials of the present invention include Kovar, Fe-Ni42wt%, Fe-
Ni42wt%-Cr6wt%, Ta, Nb, Mo, etc., preferably have a thermal expansion coefficient of 900°C or less and 10×10 ^-6 /°C or less. Ceramics that can be bonded using the clad solder of the present invention include various types of oxide-based (such as Al ₂ O ₃ ), carbide-based (such as SiC), and nitride-based (such as Si ₃ N ₄ ) ceramics. In addition, it can be bonded to a wide range of metals with a melting point of over 850°C, such as Cu-based, Fe-based, and stainless steel. (Example) An example of a clad solder according to the present invention will be explained together with a conventional example. Ag solder, intermediate material, Ag solder, intermediate material, containing an active metal having the composition shown in Table 1 below.
The Ag solder is melted in vacuum, the Ag solder containing active metal is rolled into a 3 mm thick plate, the Ag solder is similarly rolled into a 3 mm thick plate, and the intermediate material is rolled in the same way to make a 3 mm thick plate. It was made into a 6mm plate. And Example 1,
As shown in Fig. 1, 5 is made by overlapping Ag solder plate 1 containing active metal, intermediate material plate 2, and Ag solder plate 3.
In Examples 2, 4, and 6, as shown in Fig. 2, Ag solder plate 1 containing active metal, intermediate material plate 2, Ag solder plate 3, intermediate material plate 2, and Ag solder plate 3 are stacked together. ,
Examples 3, 7, and 8 are as shown in Fig. 3, including an active metal-containing Ag solder plate 1, intermediate material plate 2, Ag solder plate 3, intermediate material plate 2, Ag solder plate 3, and intermediate material. Plate 2 and Ag solder plate 3 were stacked on top of each other and bonded under pressure in a hot environment. Furthermore, hot roll pressure bonding was performed using tape material. This crimped crud filler metal has a thickness of 0.1
Rolled to mm. The active metal-containing Ag brazing plate 1 of Conventional Examples 1 and 2 was rolled from a thickness of 3 mm to a thickness of 0.1 mm.

[Table] However, the brazing materials of Examples 1 to 8 and Conventional Examples 1 and 2 were cut into length and width dimensions of 5 mm, 15 mm, and 40 mm, respectively, and these solders were used to braze ceramics and metal, in this example. Brazing of Al ₂ O ₃ , Cu and SUS304 with a thickness of 5 mm was performed in an Ar gas atmosphere furnace.
When we investigated cracks in the ceramics, ie, Al ₂ O ₃ at the brazed part, we obtained the results shown in Table 2 below.
In addition, each of the clad solders in the examples contains an active metal.
Brazing was performed with the Ag solder side placed on the ceramic side.

[Table] ○…No cracking, ×…Cracked.
As is clear from Table 2 above, according to the clad solder according to the embodiment of the present invention, Al 2 O ₃ does not crack at all when Al ₂ O ₃ and Cu are brazed, and _{Al 2 O 3}
Even when brazing SUS304, Al ₂ O ₃ rarely cracks, and only one and two layers of intermediate material are used.
Cracks were only observed when the brazing size was large, but there was no cracking at all in the case of brazing using clad brazing in Examples 3, 7, and 8, in which the intermediate material was three layers. (Effects of the Invention) As detailed above, the solder solder of the present invention can prevent the ceramic from cracking and being damaged due to stress by relieving the stress on the ceramic when brazing ceramics and metal.
Moreover, it can be said to be an epoch-making product that can replace conventional soldering because ceramics and metal can be firmly joined by brazing.

[Brief explanation of the drawing]

FIGS. 1 to 3 are perspective views showing the overlapping state of materials when making the clad solder of the present invention.

Claims (1)

[Claims] 1. Ag containing 0.5 to 8 wt% of active metal on one side using a metal or alloy with a small coefficient of thermal expansion as an intermediate material.
A clad solder characterized in that the other side of the solder is coated with Ag solder having a melting point close to that of the Ag solder, and whose liquidus temperature is 850°C or less. 2 Up to three layers of metal or alloy with a small coefficient of thermal expansion are used as an intermediate material, and Ag close to the melting point of Ag solder containing 0.5 to 8 wt% of active metal between the intermediate materials.
The wax is inserted and the active metal is applied to the outermost side by 0.5
A cladding solder characterized in that an Ag solder containing ~8wt% is covered with an Ag solder having a melting point close to that of the Ag solder containing an active metal of 0.5~8wt% on the other outermost surface. 3 The intermediate material is made of two or three layers, of which one or two layers from the outside are metals or alloys with a small coefficient of thermal expansion, and the remaining one or two layers are made of Cu, Cu alloy, Ag,
Ag alloy, Ni, or Ni alloy, with 0.5 to 8wt of active metal between these two or three layers of intermediate material.
Ag solder containing 0.5 to 8 wt% of active metal is inserted into the outermost surface of the intermediate material side of the metal or alloy with a small thermal expansion coefficient, and the Ag solder containing 0.5 to 8 wt% of active metal A clad solder characterized in that the other surface is covered with Ag solder having a melting point close to that of the Ag solder on the outermost surface.