JPS63319275A - Joined body of metal and ceramics - Google Patents

Abstract

PURPOSE:To relieve the residual stress of the joined part of a joined body of a cast iron contg. Ni at a specific ratio and ceramics by interposing a copper plate between the cast iron of said body and the ceramics. CONSTITUTION:Ti foil 2 is placed on the ceramics 1 and the Ni-contg. silver solder 3 is superposed thereon, on which the copper plate 4 is placed and further, the cast iron 8 contg. 5-50wt.% Ni is placed via silver solder thereon. The assembly is heated and held in an oxygen free furnace (electric furnace of a gaseous Ar atmosphere) and is then taken out of the furnace, by which the joined body joined with the ceramics 1 and the cast iron 8 via the copper plate 4 is obtd. The copper plate 4 exhibits the effect (plastic effect) to absorb the residual stress arising from the difference in the coefft. of thermal expansion between the cast iron 8 and the ceramics 1. The thickness of the copper plate 4 is preferably 0.5-5.0mm.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a novel metal-ceramic bonded body.

(Prior art) This type of prior art includes, for example, Japanese Patent Application Laid-Open No. 55-904.
There are some disclosed in Japanese Patent Application Laid-open No. 78, Japanese Patent Application Laid-Open No. 56-59682, and Japanese Patent Application Laid-Open No. 58-2276.

Other typical bonding methods commonly used at present include the so-called molybdenum method, in which molybdenum is baked onto the ceramic surface and metallized for metal bonding, and the active metal method, in which metallization is performed using an active metal such as titanium. There is one.

(Problem to be Solved by the Invention) Ceramics have excellent wear resistance, heat resistance, and corrosion resistance.Recently, heat-resistant ceramics have been researched mainly for engine parts with the aim of reducing weight and saving energy. There is. However, it is inappropriate and expensive to make all structural members from ceramics. or,
Although ceramics have the excellent properties mentioned above, they also have the disadvantage of being easily broken. Therefore, it is reasonable and economical to construct the necessary parts with ceramics and the rest with metals, making the best use of the characteristics of each.

For this reason, it becomes necessary to bond ceramics and metals.

However, the conventional bonding methods mentioned above, the molybdenum method and the active metal method, both require heat treatment of the objects to be joined in a vacuum or in a hydrogen stream, making the work difficult and requiring high-temperature technology. The problem was that it required

By the way, as a bonding method in the atmosphere, as shown in FIG. 7, a copper plate is inserted between ceramic A and ductile cast iron as bonding material C, and as shown in FIG. A tensile strength of about 210 kgf/c++12 was obtained when bonding was performed at temperatures above °C. In this case, the adhesion between the ceramic and the copper and between the copper and the ductile cast iron via the silver solder was very good. However, when we conducted a tensile test using this as a test piece (dimension unit = mm) as shown in Figure 7, we found that most of the fracture points d occurred near the joints of ceramics a, as shown in Figure 7. . This is thought to be due to the difference in thermal expansion between the ceramic a, the bonding material C, and the mating metal, which caused a large stress to act in the vicinity of the ceramic bond during the cooling process, which caused the fracture to occur within the ceramic a. Therefore, it is believed that if this residual stress can be alleviated, the bonding strength will be further improved.

The present invention was made from the above-mentioned viewpoint, and by selecting the metal in a joined body that joins a metal and a ceramic, residual stress at the joint is alleviated, and based on this, the metal and the ceramic have a high joint strength. The purpose is to obtain a zygote.

(Means for Solving the Problems) In order to achieve the above-mentioned object, in the present invention, in a joined body of cast iron and ceramics containing 5 to 50% by weight of nickel, a copper plate is placed between the cast iron and the ceramics. is inserted to form a joined body of metal and ceramics.

(Function) As mentioned above, when cast iron contains 5 to 50% by weight of nickel and a copper plate is inserted between the cast iron and ceramics, the coefficient of thermal expansion of the cast iron becomes close to that of the ceramics. As a result, the residual stress in the joined body of these parts is reduced, and the joint strength thereof is significantly increased.

(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 ranges from room temperature to 1,000
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-
'/'c) and temperature.

Tables 1 and 2 show the Ni content and thermal expansion coefficient (10-6
/°C).

Table 2 test results show that at low temperatures, Ni 38% DCI
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 that of Ni 44% DCI was the next lowest. The Ni 29% DCI was the highest at 18.0.

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 Al2O3.
And then ZrO2. That is, ZrO□ is 30
At temperatures up to 0°C, the coefficient of thermal expansion is 10.0 and the metal material Ni
35-44% DCI, and has a coefficient of thermal expansion of 13.5 up to 700″C, which is slightly lower 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, Δ1□03 and Ni 35~44
The coefficient of thermal expansion is relatively close to %DCI. In the case of SiC,
It has a small coefficient of thermal expansion, and the difference in coefficient of thermal expansion from that of the metal mentioned above is large, making it unsuitable for bonding.

For the reasons mentioned above, in the present invention, nickel is
Cast iron containing 50% by weight and ceramics are bonded via a copper plate.

An embodiment according to the present invention will be described below with reference to FIG. In the figure, 1 is a ceramic (A1203), and a titanium (Ti) foil 2 with a thickness of 35 μm is placed on top of this ceramic 1, and a silver solder containing nickel (150 μm thick) is placed on top of the titanium (Ti) foil 2 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 on top of that, a soft metal copper plate 4 with a thickness of 1 cylinder, and then silver solder 5.
Spheroidal graphite cast iron (containing 41% by weight of Kkel) is placed on the relaxation material with a thickness of 6 + nm through
Spheroidal graphite cast iron containing 41% by weight of nickel through 8
was placed in a non-oxidizing furnace (an electric furnace in an argon gas atmosphere) and maintained at 800 to 1000''C, and then taken out.

FIG. 2 shows another embodiment, in which spheroidal graphite cast iron 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 = mm) 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.

Furthermore, Fig. 5 shows a four-point bending test piece (dimension unit = mm) bonded using the same joining method as Fig. 1.
M is a joint located at the center, and FIG. 6 shows the bending strength in a four-point bending test when the thickness of the copper plate at the joint was varied from 0 to 5 mm.

In the above-mentioned joined bodies shown in FIGS. 1 and 2, when the thickness of the copper plate is 0.5 mm or less, and
If it is more than mm, the effect of absorbing residual stress (plastic effect) due to the difference in coefficient of thermal expansion between nickel-containing cast iron and ceramics decreases. Therefore, in the second claim, which is an embodiment of the present invention, the thickness of the copper plate is limited to 0.5 to 5 cylinders.

(Effect of the invention) As described above, when cast iron contains 5 to 50% by weight of nickel and a copper plate is inserted between the cast iron and ceramics, the coefficient of thermal expansion of the cast iron is close to that of the ceramics. As a result, the residual stress in the joined body of these parts is reduced, and the joint strength thereof is significantly increased.

Therefore, the joined body of metal and ceramics of the present invention is
It has the advantage of high bonding strength.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the first embodiment of the joined body of the present invention, Fig. 2 is an explanatory diagram of the second embodiment, Fig. 3 is an explanatory diagram of the tensile test piece, and Fig. 4 is the result of the tensile test. Figure 5 is an explanatory diagram of a four-point bending test piece, Figure 6 is a diagram showing the results of the bending test, Figure 7 is an explanatory diagram of a conventional jointed specimen, and Figure 8 is an illustration of its metallization. It is a chart showing the relationship between temperature and tensile strength. 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 procedures Indication Patent Application No. 153239 of 1988 2, Name of the invention Joined body of metal and ceramics 3, Relationship with the amended party case Patent applicant Shizuoka Prefecture Asahi Malleable Iron Co., Ltd. 4, Agent 1, Specification In page 4, line 16, change “the result will be closer” to “
2. Correct page 5, lines 15 to 17 as follows: ``The thermal expansion coefficient test used a thermal dilatometer.'' The piece was 5φ x 20mm, and both ends were polished to about 1μ.The test temperature was room temperature.'' 3. In the same page 7., line 12, ``It was low.j'' was corrected to ``It showed a small value.'' 4. In line 19 of the same page, change "lowest (,") to "lowest,"
” is corrected. 5. In line 20 of the same page, ``It was the next lowest value.'' is corrected to ``It showed the smallest value.'' 6. Correct "It was high." in the first line of page 8 to "It showed a large value."

Claims (1)

[Claims] 1. A bonded body of cast iron and ceramics containing 5 to 50% by weight of nickel, characterized in that a copper plate is inserted between the cast iron and the ceramics. zygote. 2. The joined body of metal and ceramics according to claim 1, wherein the copper plate has a thickness of 0.5 to 5.0 mm.