JPS62171970A - Member for joining 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] [Technical Field of the Invention] The present invention has excellent bonding strength. The present invention relates to a ceramic-to-metal bonding member, and more particularly to a ceramic-to-metal bonding member that uses a Ni-based alloy, Co-based alloy, or Fe-based alloy for the thermal stress buffering layer and provides excellent bonding strength.

[Technical background of the invention and its problems]

Various ceramics such as silicon nitride, silicon carbide, and alumina have begun to be widely used as structural members and various functional members by taking advantage of their unique properties. In many cases, ceramics themselves are used alone.

If it is possible to bond metal to such ceramics, it is thought that the resulting members will be able to be used in an even wider range of fields as members with new functions.

"In the case of a double series ceramic-metal bonded member, if it is a structural component, the bonding strength between the ceramic and the metal is required to be sufficiently high. In particular, it is required that the bonding strength between the ceramic and the metal be sufficiently high. High bonding strength up to high temperatures is required to take advantage of its excellent mechanical properties.

However, when ceramic and metal are directly bonded, there is a problem that cracks frequently occur in the ceramic during the cooling process, or even if no cracks occur, the ceramic is extremely susceptible to thermal fatigue or the bond strength is extremely low. This is a phenomenon based on thermal stress generated between ceramics and metal. For example, when the ceramic is alumina or silicon nitride, the linear thermal expansion coefficient of each is 8.
8X10-''/℃, 2.5X10-''/℃,
The value is about one order of magnitude smaller than that of Cu, Ni, Fe, etc., and the thermal stress generated at the joint between the two becomes large. Furthermore, the thermal stress increases as the difference between the temperature during bonding and the temperature during cooling (room temperature) increases. Therefore, in order to reduce thermal stress, it is required to lower the temperature during bonding, which requires the use of a brazing material with a low melting point during bonding.

In order to address the above-mentioned problems, a bonding method has been proposed in Japanese Patent Application Laid-Open No. 163093/1983, and a bonding member has been developed in which a brazing filler metal containing an active metal is diffused into both ceramics and metal. However, these methods have problems in terms of productivity, etc., because they require complicated steps and long-term heat treatment, and are not necessarily effective in alleviating thermal stress between ceramics and metals.

As a method for achieving stress relaxation when applying the above method, there is a method in which a soft metal layer is interposed between the ceramic and the metal, and the thermal stress is alleviated by the plastic deformation and elastic deformation (Japanese Patent Laid-Open No. 56-41879). ), a method in which a layer of a material having a coefficient of linear expansion between the ceramic and metal is interposed between the two (Japanese Patent Application Laid-open No. 1.13678/1983);
A method has been disclosed in which a plurality of layers whose linear expansion coefficients vary from small to large from ceramic to metal are successively laminated and interposed (Japanese Patent Application Laid-Open No. 1983-75/14).

However, in the case of the above-described joining method using a brazing material containing an active metal, the pressure applied to the joining surface often causes the molten brazing material to protrude from the joint. If the amount of the molten brazing filler metal that protrudes increases, cracks may occur in the ceramic during the solidification and cooling process due to thermal stress due to the difference in coefficient of thermal expansion between the ceramic and the brazing filler metal. In order to prevent this phenomenon, it is necessary to determine the optimum amount (thickness) of brazing filler metal necessary to prevent any protrusion and to wet the entire surface of the joint, but it is necessary to It is very difficult to determine the optimum amount of brazing filler metal depending on conditions such as temperature and atmosphere. Furthermore, when a thermal stress buffering layer is interposed, the interaction between the ceramics, the thermal stress buffering layer, and the brazing material becomes complicated, and bonding may not be achieved.

For example, if a Ni-based, Co-based, or Fe-based alloy is used for the thermal stress buffer layer, and an active metal brazing material is used for the brazing material,
In many cases, the active elements in the brazing filler metal are consumed to a large extent by reactions with the thermal stress buffering layer as well as the ceramics, making it impossible to obtain sufficient bonding strength.

[Purpose of the invention]

The present invention aims to provide a ceramic-metal bonding member that has high bonding strength at high temperatures and prevents cracking of the ceramic and peeling at the interface of the bonded portion due to thermal effects.

[Summary of the invention]

The inventors of the present invention have conducted extensive research on bonding members in which a stress buffer layer is interposed between ceramic and metal, and the entire body is bonded using an active metal brazing filler metal.
By using I-based alloy, CO-based alloy, or Fe-based alloy and the active metal brazing material described below as a joining brazing material, the joining strength at high temperatures is high as described above, and it is possible to prevent ceramics from being affected by heat. We have discovered a ceramic-metal bonding member that prevents cracking.

The above ceramics include 1, for example, A Qz OB g
Oxide ceramics such as ZrO□, SiC, T
Carbide ceramics such as iC, 5iaN, , A
Examples include nitride ceramics such as βN.

Examples of the above metals include Fe, Ni, Co, Ti, M
o, V.

Examples include Nb, Ta, Zr, and alloys thereof.

Examples of the thermal stress buffering layer include Ni-based alloy, Co-based alloy, and Fe-based alloy.

In addition to melting materials, these alloys are sintered bodies with a true density of 1.
The true density does not have to reach 100%, and furthermore, it may be a particle dispersion strengthened alloy with a true density of less than 100%. These alloys generally have excellent high-temperature strength and can be expected to improve bonding strength. The thickness of these thermal stress buffer layers is preferably 0.3 m or more.

The reason for this is that if the thickness of the composite layer is less than 0.3 mm, it will be difficult to effectively absorb the thermal stress generated between the ceramic and the metal, and the strength of the joint will drop significantly, and the ceramic Cracks may occur.

In the joining brazing material, which is one of the features of the present invention, the selection of the composition of the Ti brazing material is determined by the components of the thermal stress buffering layer. In other words, when the thermal stress buffer layer is a Ni-based alloy, the brazing material composition is Fj-Cu or Tj-Cu-Nj, C.

In the case of base alloys, Ti-Cu or Ti-Cu-Co
, In the case of Fe-based alloys, it is preferable to select from Tj, -Cu-Fe.

However, joining is possible without necessarily using these combinations. Wax phase components are Ti-Cu, Ti-Cu-N
i.

The eutectic component of Ti-Cu-Co and Ti-Cu-Fe alloys and the lower T1 component than the eutectic component are better, and the higher the Ti component than the eutectic component, the higher the Ni content in ceramics and thermal stress buffering layer.
Reactions with base alloys, Co-based alloys, and Fe-based alloys become complicated. In other words, a large amount of Tj is consumed in the reaction between the thermal stress buffer layer and Ti5, and the reaction with the ceramics does not take place sufficiently, making it impossible to obtain high bonding strength. Further, the brazing material may be disposed in an alloy layer or as a metal foil for each element, or by any other method. If the thickness of the brazing filler metal is less than 6 tones, it will be difficult to wet the entire bonding surface between the ceramic and the thermal stress buffer layer, which will require a very smooth bonding surface and bonding pressure, which will reduce productivity. There's a problem. Furthermore, when the thickness is 20 mm or more, joining becomes easier, but the effect of the filler layer on the joining strength becomes noticeable. In other words, the waxy phase component described above is generally brittle, and as the thickness increases,
Peeling and breakage from the brazing filler metal layer is likely to occur, resulting in low bonding strength.

〔Effect of the invention〕

As detailed above, according to the present invention, the bonding strength at high temperatures is high, and it is possible to prevent the occurrence of cracks in ceramics due to the influence of heat, and in turn, the highly reliable ceramic-metal bonding that is useful as various structural members and functional members. We can provide parts.

[Embodiments of the invention]

The present invention will be explained in detail below.

Example First, a silicon nitride cylinder with a diameter of 13 nm and a thickness of 5 mm,
Structural carbon steel with diameter 1.3 +nn and thickness 51W+ (,
TIS,S Next, the composite plate is interposed between the silicon nitride cylinder and the carbon steel disc, and the brazing material is sandwiched between the silicon nitride cylinder and the composite plate and between the composite plate and the carbon steel disc, and then the composite plate is stacked. Do not apply a pressure of 10kHz/d5
It was held under the conditions of IF'' Torr and 950° C. for 4 minutes, and then cooled in argon gas to obtain a silicon nitride-carbon steel bonded member.

Table 1 shows the material, wax phase component, and thickness of the thermal stress buffer plate, and high-temperature shear strength was measured by applying a shear path force at 600° C. to the joint members and joint surfaces.

The results are also listed in Table 1. In addition, in Table 1,
Examples 1 to 4 are written, and Comparative Examples 1 to 4 are also written together.

Table 1 As is clear from Table 1 above, the shear strength at 600°C of the bonded members of Examples 1 to 4 is as follows:
~13%, and all of them are in the higher Cu content region than Ti-Cu72vt%, which is the eutectic component of Ti-Cu, and the shear strength is all 13kg / am
``In contrast, the shear strength at 600°C of the joining members of Comparative Examples 1 to 8 was higher than that of the Ti-Cu eutectic component in Comparative Examples 1 to 3. The shear strength is lower than that of the examples because it is a Ti-C component.In particular, in Comparative Example 1, the brazing material thickness was 25 μs, so the value was very low.
Although the u co-composition component was high in Cu component, the brazing material thickness was 6
Since it was as thin as 1 tn, the value was lower than that of the example.

Agent: Patent Attorney Noriyuki Chika Same Takehanasho Hisao

Claims (1)

[Claims] 1. The thermal stress buffering layer interposed in the ceramic-metal joint is made of a Ni-based alloy, a Co-based alloy, or an Fe-based alloy, and at least a brazing material for bonding the ceramic and the thermal stress buffering layer. , Ti-Cu, Ti- with a thickness of 7 to 19 mm.
A joining member of ceramic and metal, characterized in that the joining member is made of one of Cu-Ni, Ti-Cu-Co, and Ti-Cu-Fe. 2. Claim 1, characterized in that the thermal stress buffer layer made of a Ni-based alloy and a Co-based alloy or a Fe-based alloy is a sintered material or a particle dispersion-strengthened alloy whose true density has not been reached. Ceramic-metal bonding member described in Section 1. 3. Ti-Cu, Ti-Cu-Ni, Ti-Cu-Co
The ceramic-metal joining member according to claim 1, wherein the components of the brazing filler metal for Ti-Cu-Fe joining are each eutectic component and a Ti component lower than the eutectic component.