JPS6163576A - Method of bonding ceramic to metal - 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] [Field of Application of the Invention] The present invention relates to a method for joining ceramics and metals, and is particularly applicable to mechanical structural parts, electronic parts, etc. that require precision joining while keeping the joining temperature of ceramics and metals low. The present invention relates to a method of joining ceramics and metal that is suitable for use.

[Background of the invention]

The fact that silicon carbide can be bonded by interposing Afi is described in the proceedings of the Atomic Energy Society of Japan (Autumn 1981, Bunridai, p. J44194). However, this is an example of joining silicon carbide to each other, and silicon carbide and metal, as well as silicon nitride, alumina, sialon, etc.
There is no description of joining ceramics other than silicon carbide, such as magnesia, with metals. Therefore, when bonding ceramics and metals, no consideration is given to the reduction in bonding strength due to thermal stress caused by the difference in coefficient of thermal expansion between the two. Furthermore, since the Al (insert material) inserted between the joint surfaces is completely melted during joining, molten Al may flow out of the joint surfaces.

There is a problem with precision joining. Furthermore, Al after bonding
It is also difficult to control the thickness of the insert material itself, making it difficult to obtain stable bonding strength.

[Purpose of the invention]

An object of the present invention is to provide a method for joining ceramics and metal, which can firmly join ceramics and metal with high dimensional accuracy.

[Summary of the invention]

When joining ceramics and metals, thermal stress occurs during cooling after joining due to the difference in thermal expansion coefficients between the two. As a result, the bonding strength decreases.

Here, since An has ductility, it is effective as a stress relaxation material if Al is interposed between the ceramic and the metal. However, the amount of stress relaxation is affected by the thickness of the Al. That is, when the thickness of Al between the ceramic and the metal is thin, the amount of stress relaxation is small. Therefore, in the present invention, only both skin parts of the Al insert material are melted so that the thickness of the Al insert material becomes an appropriate value, thereby preventing AM from flowing out of the joint surface during joining. .

Furthermore, when bonding ceramics and metal, if Al is directly inserted between the bonding surfaces, a weak intermetallic compound layer may be formed on the bonding surface between the 80 and the metal, and the bonding strength is low. Therefore, it is necessary to suppress the formation of the intermetallic compound layer as much as possible.

Therefore, in the present invention, in addition to the Al insert material, a material that does not react with Al and the metal to be joined to form a fragile intermetallic compound layer is inserted between the metal to be joined and the A2 insert material. ing.

Also, when the AI2 insert material is melted, A
u flows out of the joint surface, making it impossible to obtain a joined body with high dimensional accuracy. Therefore, the present invention provides □AlA
2. Melt only the skin part of the insert material.

This is intended to prevent Al from flowing out and to improve the accuracy of one dimension.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

[Example of joining carbon-silicon and Ill (Cr-Mo#lN)] Here, since Al and steel react to form a brittle intermetallic compound, a WC-Co alloy is bonded to steel in advance. An example of bonding with silicon carbide is described.

As shown in Figure 1, 1g (W in φ10X210X20)
C-Co alloy (φ10X510X5 with Kovar plate (φ1
0 Xo, 5 mn+) 3 and its steel 1
and silicon carbide 4 with Al insert material (φ10xo, s
nun) 5 in between, and in vacuum (10-
'Torr) to 6IO°C and 0.5
A bonding pressure of Kg/mm2 was applied, and heating and pressure were maintained for 30 minutes. In this case, as the AI2 insert material 5, the core material is an An-Mn alloy (0.4 mm thick) 6, and both skin parts are an Al-10% 5i-2% Mg alloy (0.05111
A clad material consisting of 111 (thickness) 7 was used.

Further, the steel 1 and the WC-Co alloy 2 have a welding temperature of 105
Diffusion bonding was carried out under the conditions of 0° C., bonding time of 30 minutes, and bonding pressure of I kg/mm 2 .

In this example, the Al insert material 5 was bonded at a bonding temperature of 610°C.
Only both skin parts (Al-St-Mg alloy) 7 are melted,
It reacts with silicon carbide 4 and WC-Co alloy 2 to bond. Since the skin portions were melted only in the vicinity of the bonding interface, the entire AΩ insert material 5 did not flow out, and the amount of shrinkage in the pressurizing direction was small, resulting in a bonded body with good dimensional accuracy. In addition, in the bending test of the joined body, 15 to 17 kg/
A high bonding strength of "nun" was obtained.

Here, when Kovar is used instead of W C-Co alloy 2, the coefficient of thermal expansion of silicon carbide with Kovar is 45.
There is a large difference above 0° C., and this difference causes thermal stress during cooling after bonding.

On the other hand, if the thickness of the Al insert material is appropriate, the Al insert material has a function of relieving thermal stress. However, as shown in FIG. 2, the thickness of the Al insert material after joining has a large effect on the joining strength (bending strength). That is, if the thickness of the insert material is thin, the thermal stress relaxation effect by the An insert material is small, and the bonding strength is low.

The bonding strength approaches the strength of the Al insert material itself and decreases. Therefore, when Kovar is used to bond silicon carbide 4 and sea bream 1, it is desirable that the thickness of Al insert material 5 after bonding be 0.2 to 0.4 mm. You can control the thickness of 5.

That is, welding temperature 610°C1 welding pressure 0.5 Kg/m
m2. Under bonding conditions with a bonding time of 30 minutes, the Al before bonding
If the thickness of the surface material 7 of the insert material 5 is 0.1 mm and the thickness of the core material 6 is 0.4 to 0.5 m+a, the thickness of the Am insert material 5 after joining is 0.1 mm. 2-0.4m
falls within the range of m.

In this example, an example of bonding between silicon carbide and a helmet was shown, but high bonding strength was also obtained between silicon nitride and steel, alumina and iron, and sialon and a tsuba as described above. The results are shown in the table below.

(y Artificial Margin) [Effects of the Invention] As explained above, according to the present invention, ceramics and metal can be joined firmly and with high dimensional accuracy.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of silicon carbide and steel joined by the joining method of the present invention, and FIG. 2 is a diagram showing the relationship between the joining strength and the thickness of the Al insert material. 1... Steel, 2... W C-Co alloy, 3... Kovar plate. 4...Silicon carbide, 5...Al insert material, 6.
...Heartwood, 7...Skin material.

Claims (2)

[Claims] 1. A method for joining ceramics and metal, in which the core material is pure Al or Al between the joining surfaces of ceramics and metal.
An insert material having a laminated structure in which both skin materials are made of an Al alloy having a composition with a lower melting point than the core material is inserted, and a metal that reacts with Al and the metal and becomes brittle is inserted between the insert material and the metal. A method for joining ceramics and metal, which comprises interposing an intermediate material having a composition that does not generate intermediate compounds, and heating and pressurizing the insert material to a temperature at which only both skin materials melt. 2. As the insert material, a laminated structure material having pure Al or Al alloy as the core material and Si-containing Al alloy as both skin materials is used, and as the intermediate material, Ni Kovar (Fe-
29%Ni-17Co alloy), Mo, W, or cermet, and is heated and pressurized to a temperature that melts only both skin materials of the insert material. A method of joining ceramics and metal.