JPS59184778A - Pressure welding of 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 Application of the Invention] The present invention relates to a method of press-welding a ceramic member and a metal member, and particularly to the above-mentioned press-welding method using ultrafine metal particles as part of the bonding material.

[Prior art]

In recent years, non-oxide ceramics such as silicon nitride, silicon carbide, and sialon, as well as so-called new ceramics such as aluminum oxide and zirconium oxide, have rapidly become popular as high-temperature, high-strength structural materials, and much research and development is being carried out. These ceramics have many uses as gas turbine blades and combustors, diesel engine cylinders and pistons, and other high-temperature mechanical parts.

However, the physical properties of these ceramics are extremely sensitively affected by factors such as composition, grain size, microstructure, and heat treatment, and the mechanism of toughening itself is also being extensively studied theoretically and experimentally. However, the current situation is that a unified interpretation has not yet been reached, and further research and development is required before it can be used as a material for mechanical structural parts.

On the other hand, attempts have been made to compensate for the above-mentioned disadvantages of ceramics by using composite materials in which ceramic members are joined to metal members, but joining metals and ceramics is one of the fields in which the technical difficulty is extremely high.

However, brazing is one of the methods of joining ceramics and metal with high bonding strength. However, when joining a ceramic member and a metal member using the conventional brazing method, it is necessary to heat the entire part of the ceramic member and the metal member, at least in the vicinity of the area to be brazed. There is a problem in that residual stress due to this is applied, and this makes it easy for the joint to break. There were still some inconveniences, such as the need for equipment such as a heating device.

[Purpose of the invention]

The purpose of the present invention is to solve the above-mentioned conventional problems and provide a bonding method that has extremely low residual stress and high bonding strength, and requires only a small investment in equipment such as a force/q heating device, which is extremely advantageous from an industrial perspective. It's about doing.

[Summary of the invention]

In order to achieve this object, the pressure welding method of the present invention involves interposing a metal powder containing ultrafine metal particles between the surfaces of the ceramic member and the metal member to be joined, and then bonding the ceramic member and the metal member. The gist of the present invention is a method of joining a ceramic member and a metal member, which is characterized by pressure-welding at a lower temperature than the conventional method.

As is well known, ultrafine metal particles are extremely active; for example, silver particles of 1 Q nm or less fuse at room temperature just by adhering to them. Therefore, when even a small amount of ultrafine particles is added to metal powder of normal particle size, the sintering temperature of this metal powder is significantly lowered.

The present invention utilizes the extremely active property of these ultrafine metal particles to perform pressure welding at a lower temperature than conventional methods, thereby significantly reducing the residual stress that occurs during bonding. In addition to reducing the amount of damage, we are also trying to simplify the equipment and mounting aspects. The present invention will be explained in more detail below.

In the present invention, the material of the ceramic is not particularly limited. Further, either dense or porous materials can be used, but it is preferable that at least the surface to be joined is made porous. This is because if the surface of the ceramic member to be joined is made porous, it will not only be compatible with the metal, but also have a sufficient anchoring effect and increase the joining strength. This is also because this porous portion acts as a stress buffer layer that buffers thermal stress after bonding. Various methods can be used to make the surface of the ceramic member to be joined porous, such as irradiating the surface with a laser beam, sintering homogeneous powder onto the surface, or dissolving a portion of the surface with acid.

Although the surfaces of such ceramics can be bonded as is by the method of the present invention, it is advantageous to perform a metallization treatment to form a thin metal film in advance, as this increases the bonding strength with metal members. be. As methods for such metallization treatment, various known methods such as various metallization methods using metal powder, thermal spraying methods, CVD methods, and PVD methods can be employed.

Moreover, various metals or alloy members can be joined as the metal members. The surfaces of these metal members may be subjected to normal treatments such as cleaning or porous treatment to increase bonding strength.

In the present invention, the metal powder interposed between the ceramic and the metal is a mixed powder of ultrafine particles and metal powder of normal particle size.

As ultrafine particles, ultrafine particles such as silver, copper, nickel, iron, gold/cobalt, and aluminum are already commercially available, but the present invention is not limited to these, and particles made of various materials can be adopted. .

A particle size of 5000^ or less is effective, but especially 1000^ or less is effective.
0 to 1000^ is suitable. In addition, the amount of ultrafine particles added to ordinary metal powder is sufficient at about 0.05% to 2% (% indicates weight%), and in particular, about 0.1 to 0.5% is preferably adopted. be done.

In the present invention, the metal powder having a normal particle size that is not an ultrafine particle is not particularly limited, but those having the following various characteristics are preferably employed. That is, first of all, powders of metals with high plastic deformability called superplastic metals are suitable.

In general, pressure welding is joining by plastic deformation, so the use of metal powder with high plastic deformability has the effect of facilitating joining. Further, powder of an alloy called a so-called superelastic alloy can also be used. Conventionally, such superelastic alloy powder could not be used for pressure welding, but in the present invention, since ultrafine particles are mixed with this powder, pressure welding is possible. However, when powder of such a superelastic alloy is used as a lever, the elastic deformability is large, so that the effect of high resistance to repeated stress is achieved. Furthermore, various malleable brazing materials such as silver solder can also be used as a powder as they are.

In the present invention, it is preferable that the ultrafine metal powder and the normal particle size metal powder are of the same quality or of the same type. That is, for example, a metal powder of a copper alloy having a normal particle size may be used for ultrafine copper particles.

Further, it is preferable that the ultrafine metal particles and the normal metal powder can be solid-dissolved. This is because the formation of harmful intermetallic compounds tends to cause embrittlement and decrease the strength of the potash joint.

Further, in the method of the present invention, the ceramic member and the metal member are joined by applying pressure, but the portion near the joint surface may be appropriately heated during this joining. However, if this heating temperature becomes too high, there is a risk that residual thermal stress due to thermal expansion will become large, so it is preferable to heat to a temperature at which such residual thermal stress does not become excessively large.

[Embodiments of the invention]

Examples will be described below, but the present invention is not limited to the following examples unless the gist of the invention is exceeded.

EXAMPLE A silicon nitride plate with a density of 83% and carbon steel (002%) were joined by the method of the present invention. That is, a thin copper film was formed on the surface of a silicon nitride plate by sputtering. The thickness of this thin film is 1-2 μm.

Next, a mixed powder of 0.5 parts by weight of ultrafine copper particles with a particle size of 500^ and 99.5 parts by weight of copper alloy powder (composition: 585% steel, 38.5% zinc, 3% iron, particle size 300 mesh under) was prepared. 1 f/c between the silicon nitride plate and the carbon steel plate.
They were joined by sandwiching them in register and applying pressure. At this time, the pressing force was 15 kf/πJ1 and the temperature was 500°C. As a result, it was confirmed that the silicon nitride plate and the carbon steel plate were firmly bonded.

Comparative Example An attempt was made to join a silicon nitride plate and a carbon steel plate using the same method as in the above example except that an alloy powder not containing the ultrafine powder was used as the powder sandwiched between the silicon nitride plate and the carbon steel plate. did. However, even if the pressurization time was extended, the silicon nitride plate and the carbon steel plate were not bonded.

〔Effect of the invention〕

According to the present invention, a ceramic member and a metal member can be pressure-welded using ultrafine particles. Therefore, the ceramic member or the metal member can be joined without heating the entire part, and the residual stress at the joint part is alleviated. Further, according to the method of the present invention, only heating is required at a temperature of about several hundred degrees Celsius, no expensive heating equipment is required, and the equipment investment is small and the handling is easy, making it extremely advantageous industrially.

Agent Tatsuyuki Unuma (1 other person)

Claims (4)

[Claims] (1) Between the surfaces to be joined between the ceramic member and the metal member,
A method for press-welding a ceramic member and a metal member, which comprises interposing metal powder containing ultrafine particles over the entire area and then press-welding the ceramic member and the metal member. (2) The ceramic member is characterized in that at least the surface to be joined is porous.
Pressure welding method described in section. (3) The pressure welding method according to claim 1 or 2, wherein the surfaces of the ceramic members to be joined are metallized. (4) The pressure welding method according to any one of claims 1 to 3, characterized in that during the pressure welding, at least the surface to be joined is heated.