JPS63319276A - Joined body of metal and ceramics - Google Patents

Abstract

PURPOSE:To improve joint strength and to decrease the fluctuation in the joint strength by interposing copper between a metal and ceramics and heating the materials in an nonoxidation furnace at the time of joining the metal and the ceramics by interposing a metal or oxide therebetween. CONSTITUTION:Ti foil 2 is placed on the ceramics 1 and Ni-contg. silver solder 3 is superposed thereon, on which a copper plate 4 is placed and further, for example, a spheroidal graphite cast iron 8 is imposed as a joining metal via silver solder 5 thereon. The assembly is held at about 800-1,000 deg.C in the nonoxidation furnace (electric furnace of a gaseous Ar atmosphere) and is then taken out of the furnace. Since this method executes the heat treatment once in the nonoxidation furnace, the generation of voids at the joint surface decreases extremely. The joint strength is, therefore, enhanced and the fluctuation in the joint strength is decreased. The stable quality is thus obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for joining metal and ceramics.

(Prior Art) This type of prior art is disclosed in Japanese Patent Application No. 160864/1986 (Japanese Patent Application Laid-open No. 1983-1990), which was previously filed by the present applicant.

In other words, the method of joining metal and ceramics shown here in which copper is interposed between the metal and ceramics is to first place a copper plate with a thickness of about 2 mm on the joining surface of the ceramic with copper titanate interposed therebetween. After heating at 1110'C for 10 minutes in an electric furnace open to the atmosphere,
The copper plate was cooled in the furnace and held at 500°C, then taken out of the furnace, and then the surface of the copper plate was polished to 1 to 3 μm, other metals were polymerized through silver solder, and it was also exposed to the atmosphere. This was done by heating at 700"C for 10 minutes in an electric furnace. (See Figure 2 of Japanese Patent Application No. 160864/1986.) In the method of bonding gold and ceramics, heat treatment is performed twice, so voids are likely to occur on each bonding surface.

As a result, there was a problem in that the bonding strength was low and the bonding strength also varied widely, resulting in inconsistent quality.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a method for joining metals and ceramics in which a metal or an oxide is interposed between the metal and the ceramics. After copper is interposed between the ceramic and the ceramic, they are heated and bonded in a non-oxidizing furnace.

(Function) As mentioned above, since the bonding method of the present invention requires only one heat treatment, when compared with the conventional method that requires two heat treatments, voids are less likely to occur on the bonding surface. becomes significantly less. Therefore, the bonding strength is increased, the variation in bonding strength is reduced, and the quality is stable.

Furthermore, since only one heat treatment is required, the work becomes simpler and efficiency is improved.

(Example) The present invention will be explained in detail below.

In order to effectively bond metals and ceramics, it is necessary to select a bonding material that does not impose undue residual stress on the ceramics, bonding material, and metal.

Furthermore, the bonding strength between metal and ceramics is largely influenced by their respective coefficients of thermal expansion. Generally, the compressive strength of ceramics is about 10 times the tensile strength. Therefore, it is preferable that a slight compressive stress is applied to the ceramics after joining, so it is preferable that the thermal expansion of the materials to be joined be slightly larger than the thermal expansion of the ceramics.

For this reason, we created metals with different coefficients of thermal expansion by changing the composition of the metals, and investigated the coefficients of thermal expansion of ceramics.

A thermal dilatometer from the Shizuoka Prefectural Industrial Technology Center was used for the thermal expansion coefficient test. The test piece was 5φ x 20mm, and both ends were polished to about 1μ. In addition, the test temperature was 1,000 yen from room temperature.
The temperature was measured up to °C, and the temperature increase rate was 5 °C/min. Table 1 shows the coefficient of thermal expansion (10-
6/''C) and temperature.

-3= Tables 1 and 2 show the Ni content and thermal expansion coefficient (10-b) of metal materials.
/°C).

Table 2-4= As a test result, at low temperature, Ni 38% OCT
had the lowest coefficient of thermal expansion. Next was Ni41% DCI. Furthermore, Ni 35%DCI, Ni 44%D
CI, and NiO%DCI.

As shown in Table 2, up to 300°C, Ni3
The 8% DCI was 6.5, the Ni 35% DCI was 7.4, and the Ni 29% DCI was 14.2. temperature is 3
At temperatures above 00°C, the coefficient of thermal expansion increased significantly. However, up to 700°C, the Ni 41% DCI is 12.
1 was the lowest, and Ni 44% DCIO was the next lowest. The Ni 29% DCI one was the highest at 18°O.

As can be seen from Table 1, in the case of ceramics, the coefficient of thermal expansion from low to high temperatures does not change much. SiC has the smallest coefficient of thermal expansion, followed by A1□03.
And then Zr0z. That is, ZrO2 is 30
At temperatures up to 0°C, the coefficient of thermal expansion is 10.0 and the metal material Ni
The coefficient of thermal expansion is 13.5 up to 700°C, which is slightly smaller than the 14.4 coefficient of thermal expansion of Ni 44%DCI.

From the above, Ni 35%DCI-Ni is used as a metal.
44%DCI has a relatively small coefficient of thermal expansion, and the difference in thermal expansion coefficient between it and ZrO□, which has a high coefficient of thermal expansion in ceramics, is small, so it seems to be suitable as a bonding condition from the perspective of the coefficient of thermal expansion. It will be done. Next, Al2O3 and Ni 35-44%
The coefficient of thermal expansion is relatively similar to that of DCI. In the case of SiC, the coefficient of thermal expansion is small, and there is a large difference in the coefficient of thermal expansion from that of the metal mentioned above, so it is considered that it is not suitable for bonding.

An embodiment according to the present invention will be described below with reference to FIG. In the figure, 1 is a ceramic (81□03). On top of this ceramic 1 is placed a titanium (Ti) foil 2 with a thickness of 35 μm, and on top of that is a nickel-containing silver solder with a thickness of 150 μm (
Ag 50 weight% weight n 15 weight%, Cd 15 weight%, C
15% by weight of U, 5% by weight of Ni) 3, and a 1 mm thick copper plate 4 made of soft metal was placed on top of it, and then 41 weights of nickel was placed on a 6 mm thick relaxation material via silver solder 5. % spheroidal graphite cast iron) 6 is placed thereon, for example, spheroidal graphite cast iron 8 is placed as a bonding metal through a silver solder 7, and this is placed in a non-oxidizing furnace (an electric furnace in an argon gas atmosphere) at a temperature of 800 to 1000 After holding at "C", it was taken out.

FIG. 2 shows another embodiment in which a bonding metal 8 is directly bonded onto a copper plate 4 via a silver solder 5 without using the relaxation material 6 shown in FIG.

Figure 3 shows a tensile test piece (dimension unit - M) made using the same joining method as in Figure 1, and Figure 4 shows the results of measuring the tensile strength of this test piece with various thicknesses of the copper plate 4. It shows.

Figure 5 shows a four-point bending test piece (dimension unit - mm) joined using the same joining method as in Figure 1, where M is the joint located at the center, and Figure 6 shows the joint. The figure shows the bending strength in a four-point bending test when the thickness of the copper plate at the section was varied from 0 to 5 mm.

(Effects of the Invention) As mentioned above, since the bonding method of the present invention requires only one heat treatment, when compared with the conventional method that requires two heat treatments, voids (vacancies) on the bonding surface are reduced. occurrence is significantly reduced. Therefore, as shown in FIGS. 4 and 6, the bonding strength is increased, the variation in the bonding strength is also reduced, and the quality is stable.

Furthermore, since only one heat treatment is required, the work is simplified and efficiency is improved.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the first embodiment of the joining method of the present invention, Fig. 2 is an explanatory diagram of the second embodiment, Fig. 3 is an explanatory diagram of a tensile test piece, and Fig. 4 is the result of the tensile test piece. Figure 5 shows 4
An explanatory diagram of the point bending test piece, and FIG. 6 is a chart showing the results of the bending test. 1...Ceramics 2...Titanium foil 3...
Nickel-containing silver solder 4...Copper plate 5...Silver solder 6...Relaxation material 7...Silver solder 8...Metal joining procedure amendment 1. Display of the case 1985 Patent Application No. 153240 2 Name of the invention Method for joining metal and ceramics 3 Person making the amendment Relationship to the case Patent applicant Shizuoka Prefecture Asahi Malleable Iron Co., Ltd. 4 Agent 1 “The bonding method is heat treatment” on page 2, line 12 of the specification.
amended to "The bonding method is heat treatment in an atmospheric furnace." 2. In the same page, page 3, line 5, ``The bonding method is heat treatment J'' is corrected to ``The bonding method is heat treatment in a non-oxidizing furnace.'' 3. Correct the following on page 4, lines 9-11. "A thermal dilatometer was used for the thermal expansion coefficient test. The test piece was 5φ x 20 holes, and both ends were polished to about 1μ. Also, the test temperature was room temperature." 4, page 6, line 2 of the same. Correct "It was low." to "It showed a small value." 5. In the 9th line of the same page, change "lowest," to "smallest,"
I am corrected. 6. In line 10 of the same page, correct "The price was the next lowest." to "The price was the next lowest." 7. In line 11 of the same page, correct "It was high." to "It showed a large value." 8, page 8, lines 17-18 are corrected as follows. ``As mentioned above, the bonding method of the present invention requires only one heat treatment in a non-oxidizing furnace, and therefore requires two heat treatments in a non-oxidizing furnace.''

Claims (1)

[Claims] 1. In a method for joining metals and ceramics in which a metal or oxide is interposed between the metals and ceramics,
After interposing copper between the metal and ceramics,
A method for joining metals and ceramics, characterized by heat joining in a non-oxidizing furnace.