JPS6287469A - Method of bonding ceramic member to metal member - 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 Industrial Application] The present invention relates to a method of joining a metal member to a ceramic member via a copper member serving as a thermal stress buffer.

This joining method can be applied, for example, to joining a pad to an automobile camshaft or joining a gas turbine shaft to another shaft.

[Conventional technology]

In order to take advantage of the properties of ceramics such as heat resistance and heat insulation, and to compensate for the weaknesses of ceramics such as toughness,
Alternatively, in order to take advantage of the advantages of both ceramics and metals, various techniques for joining metal members to ceramics have been studied.

However, since ceramics and metals have significantly different coefficients of thermal expansion (usually about 1 order of magnitude), joining ceramic and metal members generates large thermal stress at the joint, which can cause cracks in the ceramic member. This may occur. Therefore, when joining a ceramic member and a metal member, in order to alleviate this thermal stress, a soft metal member such as copper or nickel is interposed between the ceramic member and the metal member as a thermal stress buffer. is taken.

[Problem that the invention seeks to solve]

As described above, by interposing the thermal stress buffer material between the ceramic member and the metal member, cracks caused by thermal stress can be significantly improved.

However, when a copper member is used as a thermal stress buffering material, grain boundary oxidation of copper occurs when heated to about 500°C. For this reason, there was a problem that it could not be used at high temperatures of 500° C. or higher.

Therefore, it has been desired to develop a device that allows the ceramic member, copper member, and metal member assembly to be used at high temperatures of 500° C. or higher.

[Means for solving problems]

The above problem is solved by the following method of joining a metal member to a ceramic member of the present invention.

That is, the present invention is a method for joining a metal member to a ceramic member by vacuum brazing via a copper member serving as a thermal stress buffering material, the method comprising: joining a ceramic member, a copper member, and a metal member via a brazing material. The brazing material that is stacked in the same order or in the opposite order and is interposed between the copper member and the metal member is a brazing material with excellent oxidation resistance, and this brazing material is necessary for joining the copper member and the metal member. It is characterized in that the amount is equal to or greater than the amount required to cover the surface of the copper member.

In the present invention, for joining the ceramic member and the copper member,
For example, CuT brazing filler metal can be used, and vacuum brazing is limited to limited brazing (J Is
BAG-8) and vacuum brazing are performed using nickel brazing (JI
S Z3265) etc. can be used.

In the present invention, the vacuum brazing used to join a copper member and a metal member uses the amount of coarse silver solder, etc. necessary to coat the surface of the copper member in an amount necessary for joining the copper member and the metal member. The amount shall be greater than or equal to the amount added. At this time, when stacking a ceramic member, a copper member, and a metal member in this order, in vacuum brazing, coarse silver solder etc. sag due to gravity and cover the surface of the copper member when heated, but the metal member, copper member, When stacking the ceramic members one after the other, it is necessary to bend the coarse silver solder or the like in advance for vacuum brazing so that it comes into contact with the copper member.

[Effect]

According to the present invention, vacuum brazing is sometimes performed without the need to provide a separate process for covering the surface of the copper member because the extra vacuum brazing coats the surface of the copper member with a brazing material such as coarse silver solder. , the surface of copper parts can be coated. As a result, oxidation of copper at high temperatures is suppressed, and ceramic members, copper members, and metal member joined bodies can be used up to about 700°C.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

Here, FIG. 1 is a schematic configuration diagram showing an outline of a method for joining a ceramic member and a metal member according to an embodiment of the present invention.

Rectangular parallelepiped shape (40mX) made of silicon nitride (SiiNn)
A ceramic member 1 of 16mX l (In), a rectangular parallelepiped-shaped copper member 2 (16mmX1 (lnX2m)) as a thermal stress buffer, and a rectangular parallelepiped-shaped metal member 3 made of steel (SUS403) (25wmX16mX I ON). Then, as shown in FIG.
was interposed, and a coarse silver solder 5 was interposed between the copper member 2 and the metal member 30 during vacuum brazing. At this time, Cu Ti
The brazing material 4 is 16 m long between the ceramic member 1 and the copper member 2.
For vacuum brazing, the coarse silver solder 5 is placed in a 18m x 12mm area so that the entire contact surface between the copper member 2 and the metal member 3 and the side surface of the copper member 2 are covered.
The size was set to . Place the whole in a vacuum furnace and
After heating at 930° C. for 30 minutes in a vacuum of Torr or higher, the mixture was slowly cooled.

The bonding strength of the ceramic member with metal member obtained as a result was investigated. That is, a load was applied to the metal member 3 parallel to the joint surface of the thermal stress buffer material 2, and the shear strength was examined. As a result, the shear strength was 18 kg/me''. At this time, there was no abnormality on the bonded surface, but a part of the ceramic member 1 to which the thermal stress buffer material 2 was bonded was damaged.

In addition, in order to examine the bonding strength at high temperatures, ceramic members with metal members manufactured in the same manner were held at a high temperature of 700°C for 120 hours, and then the shear strength was evaluated in the same manner as above. As a result, the shear strength was 16kf/
mm”.

Incidentally, in the copper member of the ceramic member with metal member obtained in this example, oxidation was observed in the silver solder coating layer, but almost no grain boundary oxidation was observed.

(Comparative example) The difference in the comparative example from the example is that the bonding area between the copper member 2 and the metal member 3 was set to 15gXIQm, and the silver solder 5 hanging on the side of the copper member 2 was eliminated. Generally, the metal member 3 was joined to the ceramic member 1 via the copper member 2 in the same manner as in the example.

When the shear strength of the ceramic member with metal member obtained as a result was examined, it was found to be 18 kg/tsuru” to 20 kg/12. Additionally, the ceramic member with metal member manufactured in the same manner was tested at a high temperature of 500°C. After holding for 48 hours, the shear strength was examined in the same manner as in the example, and the shear strength was 1.
3+, , /, , z.

Furthermore, after holding a ceramic member with a metal member manufactured in the same manner at a high temperature of 700°C for 50 hours, the shear strength was examined in the same manner as in the example, and the shear strength was 5.
kg/m”.

Note that significant grain boundary oxidation was observed in the copper member of the ceramic member with metal member obtained in the comparative example.

As is clear from the above examples and comparative examples, it can be seen that according to the present example, the bonding strength at room temperature can be maintained even at a high temperature of 700° C., unlike the comparative example.

Although specific embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, but includes various embodiments within the scope of the claims.

〔Effect of the invention〕

As described above, according to the method of joining a metal member to a ceramic member of the present invention, the following effects are achieved.

(a) The bonded body obtained by this method can be used up to 700°C, greatly improving the range of application.

(b) Coating of the copper members can be done simultaneously at the time of joining, so the process can be simplified.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the outline of a method for joining a ceramic member and a metal member according to an embodiment of the present invention. 1-・----Ceramic member 2-------Copper member (thermal stress buffering material) 3--1--
・-Metal member 4-----1 ・-CuTi brazing material 5...--Vacuum brazing is performed by coarse silver brazing applicant Toyota Motor Corporation 1 [Lami 2@15

Claims (1)

[Claims] (1) A method of joining a metal member to a ceramic member by vacuum brazing via a copper member serving as a thermal stress buffer, the ceramic member, the copper member, and the metal member being bonded in this order or in this order via a brazing material. The brazing material that is stacked in the opposite order and interposed between the copper component and the metal component is a brazing material with excellent oxidation resistance. A method for joining a metal member to a ceramic member, characterized in that the amount is equal to or greater than the amount necessary to coat the surface of the copper member.