JPS6033269A - Metal ceramic bonding method - 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 relates to improvements in methods for joining metals and ceramics.

[Technical background of the invention and its problems]

Metals and ceramics each have different atomic bonding states,
For this reason, when joining metals and ceramics, their chemical properties such as reactivity, and physical properties such as thermal expansion coefficient and electrical conductivity differ greatly. Therefore, it is quite difficult to fully wet both parts and perform reliable metallurgical joining.

By the way, various methods shown below are conventionally known as methods for metallurgically joining metals and ceramics.

(2) A mixture of a powder containing MO-T-Wt as a main component and an organic binder is completely applied to the bonding surface of the ceramic base material, and the mixture is heated to 1400 to 1700°C in a humid atmosphere to react.

This method is usually called metallizing. Next, after applying Ni plating on the metallizing,
A metal base material (e.g. Cu base material) tpb-8 is applied to the Ni plating.
Join by using n-based solder or the like.

Such a joining method is often used in electro-miniature parts when joining a ceramic base material as an insulator and a ('u) member as a conductor.

■ A method of joining a metal base material and a ceramic base material using an alloy whose main component is a noble metal such as Au or PT, or a metal that has a low affinity for oxygen.

■ Tl at the joint between metal base material and ceramic base material.

After the presence of active metals such as Nb and Zr or active metal hydrides that are converted into active metals by heat treatment, high temperature
A method of joining under high pressure.

However, the above method (1) has the disadvantage that it requires a large number of steps and is complicated. Although the above method (■) can be joined in a simple process, it is not economical because it uses expensive precious metals, and it also requires high pressure to ensure sufficient contact between the metal base material and ceramic base material, making it difficult to deform metal. 'Unfavorable for joining electronic parts, etc. Although the above method (2) allows for strong bonding of active metals, it requires high bonding pressure and, like the above method (2), is not suitable for bonding electronic components that are sensitive to deformation.

For this reason, when active metals such as 'l'i and zr are alloyed with transition metals such as Cu, Ni, and Fe, the melting point of the active metal alone (T i ;
1720℃A11jZ r; 1860℃) and (:u,
The melting points of Ni and Fe alone (1083°C, respectively.

1453 C, 1534 C), the melting point is several hundred
Focusing on lowering the temperature, an active metal is interposed at the joint between the transition metal base material and the ceramic base material, and the joint is made to have a temperature higher than the melting point of the transition metal and active metal alloy and lower than the melting point of the transition metal. U.S. Patent No. 2.85 discloses a method for bonding a transition metal base material and a ceramic base material by heating to a high temperature to mutually diffuse atoms of a transition metal and an active metal to form an alloy, and using this alloy to bond a transition metal base material and a ceramic base material.
No. 7,663. According to this method, at the time of joining, the joint is filled with a melt of the alloy of transition metal and active metal, and the metal base material and ceramic base material are wetted, so that it is necessary to make sufficient contact between the base materials. Almost no pressure is required during bonding, and these base materials can be firmly bonded due to the effect of the active metal. However, when a thermal shock S is applied to the obtained metal-ceramic bonded member, there is a drawback that □2 cracks occur in the ceramic base material.

[Purpose of the invention]

The present invention provides a joining method that can firmly join a metal base material and a ceramic base material in a simple process without applying pressure, and can also prevent the generation of cracks in the ceramic base material even if a thermal shock is applied to the joining members. This is what I am trying to do.

[Summary of the invention]

The present inventors have conducted various studies on the generation of ceramic base material glue due to thermal shock on bonding members made by the method disclosed in the above-mentioned U.S. patent, and have found that It has been found that the amount of alloy formed between metal and active metal and the thickness of the pickle alloy layer are closely correlated with the stiffness of the ceramic base material. This correlation is thought to be due to a mechanism similar to Koji's.

That is, since metals such as transition metals or active metals and ceramics have significantly different coefficients of thermal expansion, when the temperature of the joint increases or decreases, a large stress is generated at the joint. In this case, metals such as C, u, Ni, or a Cu--Ni alloy as a completely solid material have low hardness and are soft, so they are easily deformed by the stress and are easy to completely relax the stress. On the other hand, alloys of transition metals (Cu, Ni, etc.) and active metals (Ti, Zr, etc.) are hard and difficult to deform, so if a thick layer of these alloys exists at the joint, the stress relaxation phenomenon will be small. It is thought that cracks occur due to stress being applied to the ceramic base material.

Based on these findings, the inventors of the present invention conducted further intensive research based on all of the above investigation results, and found that after a complete alloy of the metal and the active metal was formed at the joint between the metal base material and the ceramic base material, further heat treatment was performed. Continue to diffuse the alloy into all-metal parts.
By substantially eliminating the presence of a thick alloy layer in the joints of these base materials, it is possible to firmly join each base material without applying pressure as described above, and it is also possible to resist thermal shock after joining. We have discovered a bonding method that can prevent the occurrence of double strands of ceramic base material glue.

Next, the present invention will be explained in detail.

First, an active metal layer or an active metal layer and a metal layer are interposed at the joint between a metal base material and a ceramic base material. The metal used here is, for example, cu.

Examples include Nl and alloys thereof.

In addition, nitride (A7N) is used as a ceramic.

Various ceramics can be used, including ceramics such as S''8N4r BN, etc.), carbides (SiC, etc.), and oxides (AA203, etc.).Furthermore, examples of active metals include Ti and Zr. The thickness of such an active metal layer is 100 mm from the viewpoint of shortening the diffusion time.
It is desirable that the thickness be less than μm. As a means for interposing such an active gold R layer in the joint, for example, an active metal foil may be used, or an active metal layer may be applied to a metal base material by sputtering, LPC (low-pressure plasma coating), or the like. It is possible to adopt a method of interposing the film by depositing it thereon.

Next, the joint between the metal base material and the ceramic base material is heated and held in a vacuum atmosphere or an inert gas atmosphere.

In this step, it is basically not necessary to apply pressure, but if necessary, a low pressure of 0.01 to 19/- may be applied for heating. The heating temperature needs to be higher than the melting point of the alloy of the metal base material and the active metal and lower than the melting point of the metal base material. Specifically, it is formed of a metal base material kcu, Ni, or an alloy thereof, and when an active metal layer of Ti or 'lr is used, it is heated in the range of 872 to 1082°C. The holding time is determined in relation to the thickness of the active metal layer to be interposed and the heating temperature, and is set to several tens of hours to several hundred hours if the active metal layer is 100 μm or less in the above temperature range. Through such heat treatment, a liquid alloy of the parent metal and the active metal is formed in each parent metal, and continued heating causes the alloy to diffuse into the metal parent metal. In addition, if pressure is applied during heating, the pressure may be completely released when the alloy liquid is generated at the joint part, and the alloy may be diffused into the metal base material. Subsequently, when the diffusion of the alloy is completed and the alloy metal is present in a very thin layer or completely absent at the bonded portion, it is cooled while completely preventing oxidation to form a metal-ceramic bonding material.

[Embodiments of the invention]

Next, the present invention will be explained in detail.

Example 1 First, A with 15111A square and 2 ribs in thickness! N plate and 10
One U-angle, 600 μm thick oxygen-free copper plate was prepared. Subsequently, after cleaning and degreasing these plate-like bodies with trichlene and acetone, a Ti foil with a thickness of 20 μm was interposed at the joint of these plate-like bodies, and a 2×10-5T
Cera) in a hot press maintained at a vacuum level of 0.1 from above and below between the plate-like bodies? A pressure of /- was applied, and the joint portion was maintained at 930° C. by high-frequency heating. After heating, the joint melted in less than 30 minutes. Next, after releasing the pressure, the temperature was maintained at 950°C for 96 hours to diffuse the Cu-Tl alloy layer into the oxygen-free copper plate.

Thus, the junction could be obtained using an optical microscope with a magnification of 100 times.

Example 2 First, a 5iaN4 plate-like body of 15 mm square and 3 sug thick and 1
One N1 plate-shaped body of 0W1 square and 1Tsuru thickness was prepared.

Subsequently, these plate-like bodies were cleaned and degreased with trichloride and acetone, and then a ZR foil with a thickness of 20 μm and a Cu foil with a thickness of 50 μm were interposed at the joint part of these plate-like bodies, and a 2×10-Torr It was set in a hot press maintained at a vacuum level of . -Continuing, 0.1 from the top and bottom between the plate-like bodies? A pressure of /- was applied and high frequency heating was carried out to bring the joint to t-980°C. After heating, the joint melted in less than 30 minutes. Then, after releasing the pressure, 99
The mixture was held at 0° C. for 96 hours to diffuse into the alloy layer t-Ni plate.

As a result of observing the joint in the same manner as in Example 1, it was found that no alloy layer was observed, and no cracks occurred in the St, N, or plate-like bodies, and a good Ni-8isN4 joint material could be obtained. did it.

〔Effect of the invention〕

As detailed above, according to the present invention, metal base materials and ceramic base materials can be firmly joined together in a simple process without applying pressure, and even if the ceramic base material undergoes thermal shock during the forming process or after joining, cracks will not occur in the ceramic base material. We can provide all bonding methods that can prevent this.

Applicant's agent: Patent attorney Takehikomi Suzue

Claims (3)

[Claims] (1) After interposing an active metal layer or an active metal layer and a metal layer at the joint between a metal base material and a ceramic base material, the entire joint is made of an alloy of the metal base material and the active metal, or an alloy of the metal base material and the active metal. metal and ceramic, characterized in that the alloy is maintained at a temperature higher than the melting point of the alloy and lower than the melting point of the metal base material to form the alloy at the joint, and then diffused into the entire metal base material. joining method. (2) The method for joining metal and ceramic as set forth in claim 1, wherein the metal base material and the metal layer are Cu1Ni or an alloy thereof. (3) The method for joining metal and ceramic according to claim 1, wherein the active metal is Ti or Zr.