JPH0234906B2 - TANKAKEISOTODOTONOSETSUGOKOZO - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a bonding structure between silicon carbide and copper. Silicon carbide has high strength, thermal shock resistance, and chemical stability in high temperature ranges.
It is expected to have a wide range of applications as a high-temperature structural material such as high-frequency attenuators, internal combustion engine peripheral parts, and nuclear reactor peripheral parts. On the other hand, silicon carbide has a large Young's modulus and is a brittle material, so it is rarely used alone.
It is often used as a composite bonded with dissimilar materials such as metals. However, copper, which is one of the most commonly used metals to be joined, has an extremely large difference in coefficient of thermal expansion from silicon carbide, which may cause the silicon carbide to break or cause stress to remain in the ceramic, impairing reliability. Only zygotes with a small amount of conjugate can be formed. The inventors have discovered that by interposing silver, a low Young's modulus material, between silicon carbide and copper, the silver functions as a buffer material and alleviates the thermal stress caused by the difference in thermal expansion coefficient between silicon carbide and copper. I found out that it can be absorbed. The present invention has been made based on the above findings, and provides a bonding structure between silicon carbide and copper with high bonding strength. , a bonding structure of silicon carbide and copper, characterized by comprising a copper body and a silver body interposed between the metallized surface and the opposing surface of the copper body and sandwiched by brazing metal. . Also, related to the above-mentioned specific invention, the gist of the present invention is a silicon carbide sintered body having a metallized surface formed on the surface, a copper body, and a gap between the metallized surface and the opposing surface of the copper body. Silicon carbide and copper comprising a silver body interposed on the metallized surface side and a dissimilar medium interposed on the copper body side between the opposing surfaces, all of these four bodies being joined with a brazing metal. It consists in the joint structure with. The metallized surface makes it possible to easily and firmly braze silver, which is interposed as a buffer between the silicon carbide sintered body and the tangible body made of copper or its alloy, to the surface of the silicon carbide sintered body. Silver carbonate method (Japanese Unexamined Patent Application No. 130714/1982), vapor deposition method (Japanese Patent Application No. 167030/1983)
(No.) etc. by conventional means. Silver and copper can usually be easily brazed together, but from a cost standpoint it is desirable to use a small amount of silver, so when using a brazing metal whose melting point is higher than the eutectic point of 780°C, , all the silver participates in the formation of a silver-copper eutectic and loses its function as a buffer between silicon carbide and copper. Therefore, if it is unavoidable to use a brazing metal with a high melting point, such as when silicon carbide is used as a radio wave absorber in a high-frequency electron tube container inside equipment such as a klystron or magnetron, silver and copper should be used. A different type of medium must be interposed between the two. Examples of the different media include Kovar, nickel-based alloys, iron-based alloys, tungsten, and molybdenum. In addition, zirconia sintered bodies,
Ceramics, such as alumina sintered bodies, have a coefficient of thermal expansion between that of silicon carbide and that of copper.
Both surfaces facing the silver body and the copper body may be metallized. Among these, tungsten is preferred because its coefficient of thermal expansion is relatively close to that of silicon carbide. The bonded structure of the present invention is obtained by simultaneously brazing four bodies: a silicon carbide sintered body, a silver body, a dissimilar medium, and a copper body. It can also be obtained by interposing and brazing between a silicon carbide sintered body and a copper body. As the brazing metal, all metals having a melting point lower than that of silver, such as silver solder, silver-copper eutectic solder, aluminum solder, and lead-tin eutectic solder, can be used. Examples are shown below. Example 1 Porosity: 2%, silicon carbide content: 95% by weight, size
Titanium, chromium, and copper were deposited on the main surface of a 10×10×5 mm silicon carbide sintered body at a thickness of 500 Å, 500 Å, and 500 Å, respectively.
The metal was vapor-deposited in order to a thickness of 5 μm, and then a brazing metal of the type and thickness shown in Table 1 was placed on the vapor-deposited surface, and a silver plate with a thickness of 1 mm was further placed on top of it. , further place the above brazing metal on top of it,
Furthermore, after placing a copper body with a size of 10 x 10 x 5 mm thereon, samples No. 1 and No. 1 having the bonding structure of the present invention were heated at the brazing temperature and atmosphere shown in Table 1. .2 was manufactured. For comparison, sample No. 3 was produced by placing a brazing metal on the vapor-deposited surface without using a silver plate, placing a copper body on top of it, and heating it. did. Sample No. 1 and
Table 1 shows the results of measuring the shear strength of No. 2.
For sample No. 3, the shear strength could not be measured because the silicon carbide sintered body was destroyed during cooling after heating was completed.

[Table] Example 2 Titanium, chromium and copper were deposited on the main surface of a silicon carbide sintered body under the same conditions as in Example 1, and a 1 mm thick silver plate and a silver plate of 1 mm thickness were placed on the deposited surface. After dissimilar media of the type and thickness shown and a copper body of size 10 x 10 x 5 mm were stacked with the brazing metal shown in Table 2 interposed between the opposing surfaces of these four bodies, Samples No. 4 to No. 7 having the bonding structure of the present invention were manufactured by heating at the brazing temperature and atmosphere shown in Table 2. For comparison, a different medium was not used, and a brazing metal was placed on the vapor-deposited surface, a silver plate was placed on top of it, and a copper body was placed on top of it.
Sample No. 8 was manufactured by heating at the brazing temperature and atmosphere shown in Table 2. Sample No.4~No.
The results of measuring the shear strength of No. 8 are shown in Table 2.

[Table] Used.
For sample powder No. 8, the shear strength could not be measured because the silicon carbide sintered body was destroyed when it was left to cool after heating.

Claims (1)

[Scope of Claims] 1. A silicon carbide sintered body having a metallized surface formed on its surface, a copper body, and a surface interposed between the metallized surface and the opposing surface of the copper body and sandwiched between brazing metals. A bonding structure between silicon carbide and copper, characterized by consisting of a silver body. 2. A silicon carbide sintered body with a metallized surface formed on its surface, a copper body, a silver body interposed on the metallized surface side between the metallized surface and the opposing surface of the copper body, and a copper body between the opposing surfaces. A bonding structure between silicon carbide and copper, characterized in that it consists of dissimilar media interposed on the body side, and all of these four bodies are joined with a brazing metal.