JPS60255680A - Diffusion bonding process of 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 (Field of Application) The present invention relates to an improvement in a diffusion bonding method for bonding ceramics and metals with an insert material interposed therebetween.

(Prior art) Ceramics generally have excellent wear resistance, heat resistance, corrosion resistance, etc., and are often used for mechanical parts, electronic parts, etc.; However, it has disadvantages such as being difficult to process and being very expensive compared to metal. In order to solve the above-mentioned difficulty in forming and processing, desired parts can be obtained by bonding ceramics to parts obtained by forming and processing metals that are easy to form and process. ing. Diffusion bonding methods are also used for this kind of bonding, and in particular, diffusion bonding methods that involve inserting an insert material between the ceramic and metal produce a strong bonded body and are economical. This is a very effective method.

Hereinafter, the insert material is metal and will be referred to as insert material metal and base material metal, respectively, to distinguish it from the metal forming the component.

However, since bonding requires high temperatures, if the ceramic is cooled to room temperature after bonding, residual stress will occur at the bonding interface between the ceramic and the base metal due to the difference in coefficient of thermal expansion, resulting in destruction of the ceramic or at the bonding interface. There was a problem that peeling occurred. When the above high temperatures are applied, there are problems in that brittle intermetallic compounds are formed at the bonding interface and that the structure of the base metal is changed.

(Problems to be Solved) This invention was made by focusing on the drawbacks of the prior art as described above, and is a diffusion bonding method in which an insert metal is interposed between ceramics and a base metal. In,
After bonding, the residual stress generated at the bonding interface between the ceramic and the metal is minimized to prevent destruction of the ceramic and peeling at the bonding interface, as well as to prevent brittle intermetallic compounds at the bonding interface between the insert metal and the base metal. The aim is to prevent the formation of

(Structure) According to the present invention, the ceramic surface is metallized by diffusion bonding the insert material metal, which has good reactivity with the ceramic, at high temperature, and then the base material metal is bonded at a temperature lower than the bonding temperature. and diffusion bonding.

(Function) In this way, the base metal, which has a significant difference in coefficient of thermal expansion from the ceramic, is bonded at a low temperature, so after bonding,
Thermal stress of the base metal acting on ceramics can be reduced. Furthermore, formation of a fragile intermetallic compound at the bonding interface between the insert metal and the base metal and structural changes in the base metal are prevented.

(Example) In the first step, first, a ceramic ring 1 made of a silicon carbide sintered body having an outer diameter of 74 mm, an inner diameter of 62 mm, and a thickness of 3 mm was ultrasonically cleaned with acetone for 10 minutes. Next, insert material metal 2 made of pure aluminum (JIS A1050) with an outer diameter of 72 mm, an inner diameter of 64 mm, and a thickness of 0.6 mm is inserted using acetone, and the two are overlapped concentrically.
10-8 pressure was applied for 60 minutes to obtain a bonded body of the ceramic ring 1 and the metal insert material 2 by diffusion bonding.

In the second step, first, a stainless steel metal ring 3 (base metal) with an outer diameter of 85mm, an inner diameter of 60mm, and a thickness of 13mm is made.
was ultrasonically cleaned in acetone for 10 minutes. Next, the first
After rubbing the aluminum surface of the joined body in the process with a wire brush, it was overlapped concentrically with the metal ring 3 on this surface, and a pressure of 2 kg/MM was applied at a temperature of 520°C in a vacuum of about 1Q''-IQ-3 Torr. was carried out for 60 minutes.

As a result, a good joined body of ceramics/aluminum/stainless steel was obtained, and no destruction of the ceramics or peeling at the joint interface occurred even after cooling to room temperature.

That is, silicon carbide sintered body, aluminum,
Instead of joining stainless steel at the optimum joining temperature for the silicon carbide sintered body and aluminum at the same time, the silicon carbide sintered body and aluminum are joined at the optimum joining temperature 6.
The joined body obtained in the first step is bonded at 20°C, and the second step is to bond the joined body at a bonding temperature of 520°C, preferably stainless steel, on the aluminum surface of the metallized surface. This prevents the generation of residual stress at the bonding interface.

Therefore, when the silicon carbide sintered body is cooled to room temperature after bonding, the silicon carbide sintered body does not break or peel off at the bonding interface. In addition, FeAl2 and FeA#5 formed above 540°C
Since the formation of brittle intermetallic compounds such as

(Other Examples) As other examples, oxide ceramics such as alumina, magnesia, zirconia, partially stabilized zirconia, and sialon, and non-oxide ceramics such as silicon nitride may be used as the ceramics. can.

Moreover, aluminum alloys, fiber-reinforced aluminum alloys, aluminum composite materials such as aluminum clad plates, etc. can be used as the insert material metal. Furthermore, when bonding the base metal and the insert metal such as the aluminum surface bonded to the ceramic in the first step, another insert metal such as silver, copper,
Pure metals such as nickel, gold, manganese, and silicon, or alloys thereof may be used, and instead of using these as insert materials, the base metal can be plated with these and then diffusion bonded as described above.

Further, the base metal may be iron or an alloy thereof other than stainless steel. Furthermore, other metals can also be used as insert material metals.

The insert material metal in the first step is not limited to a sheet shape, but may be a thin plate shape or a foil shape, and it is desirable that consideration be given to reducing residual stress after joining.

In addition, when joining insert metal and base metal, if the joining surface is cleaned using a mechanical or physicochemical method in a vacuum or the like immediately before joining, it becomes possible to join at a lower temperature. .

Further, the atmosphere in which diffusion bonding is performed can be in addition to vacuum, inert gas, reducing gas, or air.

The pressure applied during diffusion bonding is preferably approximately 0.5 to 5 kg/Ni.

The effects of these other embodiments are the same as those of the first embodiment.

Note that for bonding the ceramic and the metal insert material, that is, metallizing the surface of the ceramic, methods other than equidiffusion bonding such as plating, vapor deposition, ion blasting, and brazing can also be used.

Furthermore, methods other than diffusion bonding, such as brazing and soldering, can be used to bond the insert metal and the base metal.

(Effects) As described above, according to the present invention, in the diffusion bonding method of ceramics and metal using an insert material, the residual stress generated at the bonding interface can be reduced, thereby preventing the destruction of the ceramics. It has the remarkable effect of preventing peeling at the bonding interface. Furthermore, since the formation of brittle intermetallic compounds at the joint interface is prevented, there is also the effect of improving the joint strength.

[Brief explanation of drawings]

The drawings show an embodiment of the invention, with FIG. 1 being a side view and FIG. 2 being a plan view. In the drawings, 1 is a ceramic ring, 2 is a metal insert material, and 3 is a metal ring.

Claims (1)

[Claims] In a diffusion bonding method for bonding ceramics and metal with an insert material interposed, the ceramic and the insert material are bonded at a high temperature, and then the insert material and the metal are bonded at a low temperature, A diffusion bonding method characterized by obtaining a bonded body of the ceramic and metal.