JPH03109275A - Method for joining metal to ceramics - Google Patents

Abstract

PURPOSE:To attain airtight firm joining without using a binder by engaging a metal with ceramics by a specified structure and carrying out mechanical joining. CONSTITUTION:When a metal is joined to ceramics, the ceramics 2 is embedded in the metal 1 and a part or the whole of the embedded part of the ceramics 2 is tapered 3, protruded 4 or recessed 5. Two or more of tapering, protruding and recessing stages may be carried out in combination. The ceramics 2 is fixed in the metal 1 and joined by constant-temp. forging.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to an integrally molded product of metal and ceramics. More specifically, it relates to a joining method of fitting and embedding ceramics into metals.

[Summary of the invention 1] The present invention provides a method for bonding metals and ceramics by inserting a bonding material into the interface between the metals and ceramics, and changing the bonding atmosphere to an inert gas or high vacuum. There was also the problem that the strength after bonding was weak. Therefore, by embedding ceramics into metal during the metal forming process, we have made it possible to bond metals and ceramics not only in an inert gas atmosphere or vacuum atmosphere, but also in the air, without using a bonding material. be. [Prior Art] Conventionally, when joining ceramics to metal, the metal was previously formed into a final shape and then the ceramic was joined to the molded product. In that case, in order to firmly join metal and ceramics, a brazing filler metal 4 having a relatively high melting point is used for the joining, as shown in FIG. When joining using a brazing filler metal, a metallized layer 5 is applied to the ceramic joint.
In addition, it is necessary to apply a metal coating 5', and it is also necessary to prevent surface deterioration such as oxidation and adhesion of impurities on the bonding surface between the metal and the ceramic. Therefore, the bonding is performed in a vacuum or with impurities such as argon. This requires the use of an active gas atmosphere or an atmosphere that does not generate a surface-altered layer, which necessitates the use of an atmosphere device for bonding. Furthermore, the shape of the metal and the shape of the ceramic at the joint surface had to match, and the surface roughness had to be controlled. [Problem to be solved by the invention] When joining metal and ceramics using a brazing material, good adhesion cannot be achieved if there is a deteriorated layer such as oxidation or adhesion of impurities on the joint surface.When joining metal and ceramics. , the brazing metal must be heated to a temperature that melts it, and oxidation and impurity adhesion are likely to occur. Therefore, a vacuum or inert gas is required in the bonding atmosphere, and an atmosphere furnace must be used. Equipment becomes expensive. Additionally, since ceramics must be joined without deforming the metal,
It is necessary to match the bonding surfaces of metal and ceramic. Ceramics are difficult to process, and therefore joining with complex joint surfaces is difficult, and is limited to simple shapes. Bonding using brazing filler metal has low bonding strength and large variations, making it difficult to use in areas where force is applied due to low reliability.Some brazing fillers have poor corrosion resistance, so be careful when selecting the filler metal. Must. [Means for Solving the Problems 1 Therefore, in the present invention, in order to solve these problems, ceramics are fitted to metal during the process of forming the metal,
The metal and ceramics were mechanically joined by interlocking with each other by constant temperature forging without using any joining material. The shape of the metal for inserting the ceramic has a recess for inserting the ceramic, and the ceramic is inserted into the recess. Taper the part of the ceramic that comes into contact with the metal. The taper is made larger at the tip. Further, a convex portion may be provided instead of a taper. By performing isothermal forging in this state, metal fills the ceramic and mechanically joins the metal and ceramic. [Operation] Metal is formed into a state in which a portion into which ceramics is inserted is provided. Ceramics with tapered parts, protrusions, and recesses are inserted into the metal at the joint surface, and constant temperature forging is performed. After forging, the metal and ceramic are joined without using a joining material. [Example 1] First, to explain the basic background of the present invention, when attempting to make metal and ceramics by cold forging or hot forging, the forming load becomes large and the ceramics break. By using forging, the forming load can be reduced and the adhesion between the metal and the ceramic can be improved without destroying the ceramic. Examples of the present invention will be described based on this background. FIG. 1 is a cross-sectional view of metal and ceramic bonding. The metal and the ceramic are bonded by embedding the ceramic 2 in the metal 1. At the joint, taper 3 to the ceramic so that the tip is larger. With the structure shown in FIG. 1, metal and ceramics can be mechanically bonded without using a bonding material at the interface between the metal and ceramics. FIG. 2 is a sectional view of a conventional metal-ceramic bond. A metal 1 and a ceramic 2 were bonded together using a bonding material 4. In conventional methods, the bonding strength is affected by the bonding material and cannot be increased, and is particularly weak against shearing force. - In the method shown in Fig. 1, the bonding strength is the strength of metal or ceramics, and is extremely thick. Fig. 3 shows an embodiment of the present invention. A strong bond with the metal was also obtained.Next, the forming process of the present invention will be explained.Figure 4 is a cross-sectional view showing the method of bonding metal and ceramics according to the present invention.The metal 1 and the ceramic 2 were processed in advance. The ceramic 2 has a taper in the part embedded in the metal l.
Ceramics 2 are inserted into the recesses of the zero-order gold 51, in which a convex portion or a recess is formed, and the metal is deformed and joined to the ceramics 2 by constant-temperature forging. The reason why metal is deformed by isothermal forging is that by deforming metal at a constant temperature, the deformation stress can be reduced to a fraction of what it should be, and large elongation can be obtained, so the metal and ceramic can be brought into close contact without destroying the ceramic. It is from. When cold or hot forging was performed, a large load was applied and the ceramics were destroyed. In addition, the metal and ceramic did not come into close contact due to metal springback. Since it is necessary to keep the mold at a high temperature in order to perform constant temperature forging, the mold was heated by the heater 6. By maintaining uniform heating at a specific temperature and applying a specific processing speed, only the metal exhibited low stress deformation and high elongation, and the metal and ceramic were firmly bonded without deforming the ceramic. In addition, the gap between the metal and ceramics was close and airtightness was good. Regarding corrosion,
Only metal and ceramic materials need to be considered;
There is no need to consider the corrosion resistance of bonding materials as in the past, and the range of material selection has expanded. [Effects of the Invention] As described above, according to the present invention, by mechanically joining metal and ceramics by interlocking, not only a strong joint can be achieved, but also airtightness can be obtained, and corrosion resistance of the joining material can be improved. There is no need to think about this (in terms of corrosion, the range of choices between metals and ceramics is expanded and it provides an effective joining method.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing a state of bonding between a metal and a ceramic according to the present invention, FIG. 2 is a cross-sectional view showing a state of a conventional bond between a metal and a ceramic, and FIG. FIG. 4 is a sectional view showing an example of joining metal and ceramics. FIG. 4 is a sectional view showing a method of joining metal and ceramics according to the present invention. ■...Metal 2...Ceramics 3...Taper 4...Joining material 5...Mold 6... -Heater or higher

Claims (1)

[Claims] In joining metal and ceramics, the ceramic is embedded in the metal, and a part or the entire surface of the embedded part of the ceramic is provided with one of tapers, protrusions, or recesses, or two or more sets of tapers, protrusions, and recesses. A method for joining metal and ceramics, characterized in that the metal and the ceramic are fitted together and joined by constant temperature forging.