JPS59164677A - Ceramic metal bonding method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a method of joining ceramics and metal.

C) Technical background of the invention and its problems) When ceramics are used as materials in various fields, it is desirable to use them by joining them to metals that are dissimilar materials. This is because the range of uses is far greater in terms of strength, etc. than when ceramics are used alone. Conventionally, there have been various methods for joining ceramics and metals. Namely, there are five methods such as mechanical joining, organic or inorganic adhesives, brazing, etc., but all of them have problems with the strength, airtightness, etc. of the joint. One of the problems with these conventional methods is that there is a large difference in coefficient of thermal expansion between the ceramic, the metal to be joined, and the brazing filler metal, which tends to cause breakage due to thermal stress during the cooling period after joining. can be given. Furthermore, problems caused by this difference in thermal expansion coefficients occur not only when heating is applied during bonding, but also when a ceramic-metal bonded body is used under complete heating. for example.

When ceramics are bonded to the inner surface of an engine cylinder liner, thermal stress due to the temperature difference that exists between the ceramics and the liner becomes a problem.

Examples of the thermal expansion coefficients of ceramics and metals are listed below.

At, 0. Ceramic near, 8X10 KSi,
N4 ceramics; 3.2X10 KSiC ceramics: 4.8X] OK ZrO, ceramics = 9 ×10 KFe metal
F12X10 KAt alloy: 2
3X10 KCu alloy: 17X10
K (Object of the Invention) The present invention has been made in view of the above-mentioned problems, and provides a bonding method that can maintain a strong bond between ceramics and metal, despite the large difference in coefficient of thermal expansion between the two. The purpose is to provide.

(Structure and operation of the invention) The method for joining ceramics and metal of the present invention is to form a metal coating on the bonding surface on the ceramic side by chemical vapor deposition or physical vapor deposition, and then between this metal coating and the bonding surface on the bonding metal side. The method is characterized in that a mixture containing a superplastic metal is fully inserted and the mixture is compression-molded in a mold to perform the bonding, and a superplastic metal layer is provided between the bonding surfaces to prevent thermal expansion. The thermal stress caused by the difference in rate can be absorbed.

■ Superplastic metals include Zn-At alloy and Bi-Sn alloy.

Cu-P alloy, Pb-Sn alloy, Cd-Z'n alloy, M
There are alloys such as g-At alloy. In general, superplastic metals are 1μ
It consists of a structure with very fine equiaxed crystal grains of less than m in size, and the plastic deformation sound slows down by several hundred percent in response to small external forces at a temperature of approximately 1/2 of the absolute melting point of the alloy. arise. This superplastic phenomenon also appears when the entire powder or fiber having an internal structure of about 1 μm or less is compression molded. The present invention is a joining method using a compression molded body of superplastic metal powder or fiber.

(2) It is desirable that the mixture of superplastic metal powder and metal powder has a weight of 5:1 and contains 1Qwt% or more of superplastic alloy. The metal powder improves so-called conformability during compression molding and makes the bond stronger.

In addition, the thermal expansion coefficient of the mixture itself can be fully adjusted by changing the mixing ratio, and the difference in thermal expansion coefficient with the joining metal and the difference in the thermal expansion coefficient with ceramics can be minimized.

Furthermore, the superplastic metal contained in the mixture also has the function of applying compressive force during compression molding evenly to the mixture, making joining easier.

■ It is also possible to provide a coating layer of a metal film on the superplastic metal powder or fiber, and in this case, the adhesion to the coating metal on the ceramic can be improved compared to the case of a mixture of superplastic metal powder and metal powder. , it can be made even smoother.

(2) Chemical vapor deposition, which is a means of forming a metal coating on the ceramic surface, involves depositing the metal coating on the ceramic surface by evaporating the ceramic into a gas phase in which a chemical reaction is occurring to deposit the metal coating. Also, physical vapor deposition is 1
For example, there is a method called sputtering deposition,
Ar is caused by glow discharge in an atmosphere such as r gas.
When the Ar ions are ionized and collide with the coating metal material disposed on the cathode, coating metal atoms are released and deposited on the ceramic surface. When coating the superplastic metal powder with a metal film, chemical vapor deposition or physical vapor deposition is used in the same manner as described above. The coating metal on the ceramic, the metal powder mixed with the superplastic metal powder, and the coating metal coating the superplastic alloy powder do not necessarily have to be the same metal as the bonding metal, but the bonding properties of the superplastic alloy and the A good one is desirable.

(Example of the invention) A first embodiment of the present invention will be fully explained with reference to FIG.

In this example, the ceramic 1 is AttOs'z
The main component is alumina ceramics. Further, the bonding metal 2 is metallic copper. The superplastic alloy used is Zn −
It is an At alloy (22 wt% At), and 60 wt% is present in the metallic copper powder 4. The coating metal 5 is copper metal, and the thickness of the coating is approximately 40 μm. The coating was formed by physical vapor deposition. Specifically, metallic copper is deposited on alumina ceramics by colliding Ar ions with metallic copper disposed on the anode using a sputtering vapor deposition method. Next, compression molding using a press mold produces powder consisting of a Zn-At alloy with an internal structure of approximately 1 μm and an average powder particle size of 40 μm.
A mixture with a powder consisting of 1-5 μm fine particles of metallic copper was heated in a hydrogen atmosphere at a temperature of 380°C and a compressive force of 30 kHz/-.
After holding for 0 minutes, it was cooled. Through this heating and compression, the thickness of the mixture of superplastic metal powder and metallic copper powder is approximately 10 mm.
It became 0 μm.

The bonded body of ceramic 1 and metal 2 bonded according to this first example had a much better bonding condition than that of ceramic and metal bonded using a brazing filler metal, and no damage to the bonded surfaces such as peeling was observed at all. Ta.

The first example above uses a mixture of superplastic metal powder and metal powder, but the second example described below uses a metal film around the superplastic metal powder. The coated powder was used entirely, and is explained in FIG. In this second example, the superplastic metal powder 3 is the same as in the first example <Zn-At alloy (22wt%A7)
The metal copper 8 is coated around it. Specifically, Zn was deposited in a sputtering vapor deposition apparatus shown in FIG.
A metallic copper coating of approximately 15 μm was applied around the -At alloy. That is, as shown in FIG.
The metal copper to be coated is placed on the substrate, and the superplastic metal powder 3 is placed on the base side.
The powder tank 13 has an opening facing the target 12 and has a powder stirring means inside. Thereby, the copper atoms or molecules scattered from the metal copper on the target 12 side can be uniformly added to the entire superplastic metal powder.

The conditions for coating metallic copper on the ceramic and the conditions for heating and compression were the same as in the first example.

Similarly to the bonded body of the first example, no destruction of the bonded surface was observed in the ceramic-metal bonded body of the second example.

(Effect of the invention) According to the ceramic-metal joining method of the present invention.

Despite the large difference in coefficient of thermal expansion between ceramics and metals, a strong bond between the two can be maintained.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of a joint according to a first embodiment of the present invention;
FIG. 2 is a longitudinal sectional view of a joint according to a second embodiment, and FIG. 3 is a longitudinal sectional view of a sputtering vapor deposition apparatus for forming a metallic copper coating on the superplastic alloy powder of FIG. 2. 1... Alumina ceramics, 2... Metallic copper. 3... Superplastic metal powder (Zn-At), 4... Metallic copper powder. 5...Metal steel coating, 6...Heater 7...
Mold, 8... Metal steel coating, 11... Sputtering vapor deposition equipment. 12° target, 13...powder bath. Agent Tatsuyuki Unuma (and 2 others) Figure 1↓

Claims (1)

[Claims] (1) In a method for joining ceramics and a joining metal to be joined thereto, a metal coating is formed on the joining surface of the ceramic by chemical vapor deposition or physical vapor deposition, and then this metal coating and the joining metal are bonded together. A method of bonding ceramics and metals by inserting a mixture of superplastic metal powder or fibers and metal powder between the side joint surfaces, and compression-molding this mixture in a press mold. Joining method. C) The method of joining ceramics and metal according to claim 1, wherein the compression molding is performed by heating compression. (3) A method for joining ceramics and metal according to claim 1, wherein the mixture contains 10 wt% or more of superplastic metal powder or fibers. (4) % Permissible The method of joining ceramics and metal according to claim 1, wherein the superplastic metal powder or fiber is coated with a coating metal.