JP2760987B2 - Joining method of ceramics and metal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a method for joining ceramics and metal. (Prior Art) Recently, ceramics have begun to be used in a wide range of fields such as structural materials and functional materials due to their excellent characteristics. In many cases, the components are composed of ceramics alone, but in order to use ceramics in more fields, it is necessary to be able to bond with metals. For this reason, it is desired to confirm the joining method between ceramics and metal. However, in general, the thermal expansion coefficients of ceramics and metals are greatly different, and thermal stress is frequently generated at the joint due to the difference in the thermal expansion coefficients of the two. These thermal stresses have an important problem that cracks are easily generated in ceramics. Therefore, in order to reduce the occurrence of such thermal stress, a joint using a ceramic and a metal having a coefficient of thermal expansion close to each other has been studied as much as possible. Examples of the metal used for such a purpose include an iron-based alloy having a low coefficient of thermal expansion such as an Fe-Cr alloy, a Fe-Ni-Cr alloy, or an Fe-Ni alloy, which is commonly called Kovar or 42 alloy. . If an Ag-based brazing material used for joining ordinary ceramics and metals is used when joining these iron-based low heat, expansion alloys, the components of the brazing material will easily penetrate (penetrate) around grain boundaries, Causes deterioration. To prevent this, for example, as shown in WeldJ, 61-11, p363, it has been attempted to provide a Ni plating layer on the joining layer surface of an iron-based low thermal expansion alloy, but in this case, Ni is contained in the brazing material. It has been confirmed by experiments that it diffuses and adversely affects the bondability between ceramics and brazing material. This problem has been an important drawback particularly when joining for obtaining a container or the like that protects airtightness. (Problems to be Solved by the Invention) The method of the present invention has been made in view of the above points,
An object of the present invention is to provide a method for joining ceramics and metal, which enables good joining. [Constitution of the Invention] (Means and Actions for Solving the Problems) The method of the present invention comprises the steps of forming a ceramic and an iron-based alloy having at least one coating layer of Cu and Cr on a joint surface and containing at least Ni. A method of joining a ceramic and a metal, in which a bonding layer containing an active metal and an Ag-based brazing material is provided therebetween, and then the ceramic and the iron-based alloy containing Ni are joined by heating. A brazing material layer provided with an active metal powder layer on the side is used. In other words, according to the method of the present invention, by providing a coating layer such as Cu and Cr on the joint surface of the iron-based alloy containing Ni, the iron-based alloy containing at least Ni by the brazing material does not cause penetration and the coating layer is not formed. Since the components are not diffused into the brazing material, the ceramics and the metal can be bonded well with good adhesion. The ceramic used in the present invention is alumina,
Oxide ceramics such as forsterite, non-oxide ceramics such as aluminum nitride, and non-oxide ceramics such as aluminum nitride can be used. Also, Ni-containing iron-based alloys include Fe-36Ni, Fe-42Ni
For example, an Fe-Ni alloy, an Fe-Ni-Co alloy such as Fe-29Ni-17Co, or the like can be used. Also, as a method of forming a coating layer of Cu, Cr, etc. provided on a joint surface of an iron-based alloy containing at least Ni, various methods such as plating, sputtering, vapor deposition, and CVD can be mentioned. The plating method is advantageous from the viewpoint of the formation speed and the like. The thickness of the layer is not particularly limited, but is preferably 1 μm to 100 μm in consideration of the barrier effect on the brazing material. The Cu or Cr layer need not be formed as a single layer,
And a Cr layer may be provided, or another layer such as a Ni layer may be provided on the surface of the iron-based low thermal expansion coefficient alloy, and then the Cu layer may be provided.
Alternatively, a Cr layer or both may be provided. Next, as a bonding layer containing an active metal and a brazing material used in the present invention, Ti-Ag-Cu, Zr-Ag-Cu, Ti-Ag Cu-Sn, etc. It is preferable to use a brazing material layer provided with metal powder. In this case, an active metal powder having a particle size of about 1 to 50 μm is used, and it is preferable to use about 0.1 to 10 mg / cm ² . In addition, Ag-Cu, Ag-Cu-Sn, Ag-Cu-Sn-In alloy, etc. can be used as the brazing material layer. The temperature, atmosphere, pressure, etc., at the time of joining can be set as appropriate, but in practice it is preferably 700 to 900 ° C., in a vacuum, and the time is 1 minute to 30 minutes. May be added to the extent that they adhere. [Example] (Example 1) As shown in FIG.
Al ₂ O ₃ ceramic container with an inner diameter of 50 mm and a height of 60 mm (1)
Was prepared. Next, a mixture was prepared by kneading a 9: 1 mixed powder of Ti and Zr having a diameter of 5 μm or less with an ethanol solution of ethyl cellulose, and a bonding surface of the ceramic container (3) was prepared.
And (3) '. At this time, the applied amount is 1m
g / cm ² . Thereafter, 50 μm thick plates (4) and (4) ′ of Ag brazing (72% Ag—Cu) were disposed on the coating surface, and after forming a bonding layer, Ni with a 10 μm Cr plating on the surface was further applied. The sealing metals (2) and (2) 'made of copearl (Ni-Co-Fe alloy) as an iron-based alloy to be contained are brought into contact with each other, and then placed in a vacuum (2 × 10 ^-5 Tor
In r), the mixture was heated and maintained at 850 ° C. for 5 minutes. After being taken out of the furnace after cooling, the ceramic container and the metal to be sealed were favorably formed by the Ag solder (5) flowing so as to draw a hem to the joint surface of the metallized ceramic container as shown in FIG. It was firmly fixed with good adhesion. When the airtightness at the joint was evaluated by a He leak test, the He leak amount was 10 ⁻¹⁰ Torr · l / sec or less, and there was no leak. (Example 2) An outer diameter of 60 mm was used as ceramics as shown in FIG.
Al ₂ O ₃ ceramic container with an inner diameter of 50 mm and a height of 60 mm (1)
Was prepared. Next, a mixed agent was prepared by kneading a 9: 1 mixed powder of Ti and Zr having a diameter of 5 μm or less with an ethanol solution of ethylcellulose.
And (3) '. At this time, the applied amount is 1m
g / cm ² . Then, 50 μm thick plates (4) and (4) ′ of Ag braze (72% Ag-Cu) are arranged on the coating surface, and after forming a bonding layer, the surface contains Ni plated with 20 μm Cu. A further 42 alloy (Ni-Fe alloy) sealing metal (2) or (2) ′ as an iron-based alloy was brought into contact with the alloy, and was placed in a vacuum (2 × 10 ⁻⁵ Torr).
In r), the mixture was heated and maintained at 850 ° C. for 5 minutes. After being taken out of the furnace after cooling, the ceramic container and the metal to be sealed were favorably formed by the Ag solder (5) flowing so as to draw a hem to the joint surface of the metallized ceramic container as shown in FIG. , Was firmly fixed. The airtightness at the joint was evaluated by a He leak test.
^{It was -10} Torr · l / sec or less, and there was no leakage. (Example 3) An outer diameter of 60 mm was used as a ceramic as shown in FIG.
Al ₂ O ₃ ceramic container with an inner diameter of 50 mm and a height of 60 mm (1)
Was prepared. Next, a mixture was prepared by kneading a mixed powder of 1% Ti-71% Ag-28% Cu with an ethanol solution of ethyl cellulose, and applied to the bonding surfaces (3) and (3) 'of the ceramic container, respectively. . At this time, the coating thickness is 40μ
m. After that, Kovar (Ni-Co-Fe alloy) as an iron-based alloy containing Ni with a 10 µm Cr plating on the surface
Metals (2) and (2) ′ for sealing were brought into contact with each other, and heated and maintained at 850 ° C. for 5 minutes in a vacuum (2 × 10 ⁻⁵ Torr). After being taken out of the furnace after cooling, the ceramic container and the metal to be sealed were, as shown in FIG. 2, activated Ag that flowed so as to draw a hem to the joining surface of the metallized ceramic container.
The wax (5) was firmly fixed with good adhesion and good adhesion. When the airtightness at the joint was evaluated by a He leak test, the He leak amount was 10 ⁻¹⁰ Torr · l / sec or less, and there was no leak. [Effects of the Invention] According to the present invention, ceramics and metal having good adhesion can be joined.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing the structure of a container in an embodiment of the present invention, and FIG. 2 is an enlarged schematic diagram showing a joint. 1 ... Ceramic container, 2,2 '... Metal, 3,3'
…… joint surface, 4,4 ′… Ag brazing plate, 5… Ag brazing.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hiromitsu Takeda 1 Toshiba, Komukai Toshiba-cho, Saisaki-ku, Kawasaki-shi, Kanagawa Prefecture (56) References JP-A-61-136970 (JP, A) JP-A Sho 57-129882 (JP, A) JP-A-60-200868 (JP, A) JP-A-62-182166 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C04B 37/00 -37/04 B23K 1/19

Claims (1)

(57) [Claims] A step of forming a coating layer containing Cr on the surface of an iron-based alloy containing Ni, and a step of joining the iron-based alloy and ceramics through the coating layer using an Ag-based brazing material. The method of joining ceramics and metal. 2. 2. The method according to claim 1, wherein the Ag-based brazing material contains an active metal powder. 3. The method according to claim 1, wherein the coating layer is formed by a plating method.