JPH0369864B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for joining ceramics and metal.

BACKGROUND ART Ceramics are used for various purposes because of their excellent heat resistance, wear resistance, insulation properties, etc. Depending on these uses, it may be necessary to join a ceramic member and a metal member. For example, when ceramics are used as a structural member, they are often used as a bonded body with metal because ceramics have poor impact resistance. In order to bond ceramics and metal in this way, it is necessary to metalize the surface of the ceramics in advance.

As methods for metallizing ceramics, the Telefunken method, active metal method, hydride compound method, oxide solder method, silver carbonate method, etc. are known, but methods other than the Telefunken method are rarely used. This is because not only the process is complicated, but also the adhesive strength, thermal shock resistance, chemical resistance, etc. of the obtained metallized layer are often insufficient.
In the currently commonly used Telefunken method, the ceramic surface is coated with molybdenum-manganese, baked at a high temperature of about 1400 to 1700°C in a non-oxidizing atmosphere, then metal plated, and then again non-oxidized. By heating in a neutral atmosphere, a stabilized metallized layer is formed. However, this method also requires a complicated multi-step process and has drawbacks such as high heating temperature.

Means for Solving the Problems The present inventor has conducted extensive research in order to find a method for bonding ceramics and metals that has excellent heat resistance, high adhesive strength, and excellent uniformity of quality. . As a result, a specific oxide was made into a paste using screen oil, etc., and then applied onto ceramics and heated in an oxidizing atmosphere.
After forming a baking layer on ceramics, silver solder is placed on top of this, a metal member is placed on top of this, and the metal member is then heat treated in a reducing atmosphere to strengthen the metal member in a simple manner. discovered that it could be bonded to ceramics.

Through further research, the present inventor placed silver solder on the baking layer in the same manner as the above method,
Next, an intermediate material having a coefficient of thermal expansion between that of the metal parts to be joined and ceramics, silver solder, and metal parts are sequentially placed on top of this, and then heat treated in a reducing atmosphere to easily achieve extremely high heat resistance. It has been discovered that a bonded body of ceramics and a metal member with excellent properties can be obtained. The present invention is based on these findings.

That is, the present invention provides the following method for joining ceramics and metal.

A paste containing NiO and Cu ₂ O and/or SiO ₂ is applied onto ceramics and baked in an oxidizing atmosphere, then silver solder is placed on the baked layer, and the metal to be joined is placed on top of this. 1. A method for joining ceramics and metal (hereinafter referred to as the first invention of the present application), characterized in that the ceramics and metal are placed and heat treated at 600 to 900°C in a reducing atmosphere.

A paste containing NiO, Cu ₂ O and/or SiO ₂ is applied onto ceramics and baked in an oxidizing atmosphere, then silver solder, intermediate material, silver solder and metal to be joined are sequentially applied on the baked layer. 1. A method for joining ceramics and metal (hereinafter referred to as the second invention of the present application), characterized in that the ceramics and the metal are placed and heat treated at 600 to 900°C in a reducing atmosphere.

Ceramics to which the method of the present invention can be applied are not particularly limited, and include non-oxide ceramics such as silicon nitride, sialon, silicon carbide, and aluminum nitride, and oxide ceramics such as alumina, zirconia, mullite, beryllia, magnesia, and cordierite. can be mentioned.

The paste used in the method of the present invention is NiO
It is also necessary to contain Cu ₂ O and/or SiO ₂ . Specific oxide combinations include a) NiO and Cu ₂ O, b) NiO and SiO ₂ , c)
There are three types of NiO, Cu ₂ O and SiO ₂ , and the blending ratio of each component in the combination of these three types is a) 80 to 50% by weight of NiO and 20 to 20% of Cu ₂ O.
50% by weight, b) 80-95% by weight of NiO and
20-5% by weight of _SiO2 ; in c), 50-80% by weight of NiO, 45-15% by weight _{of Cu2O} and 5-10% by weight _of SiO2.

The above-mentioned oxides are usually used in powder form. Although the particle size is not particularly limited, it is preferably about 2 to 1 μm or less. Moreover, kaolin can also be used instead of SiO ₂ . In order to form these into a paste, a binder or the like may be added as appropriate to the mixture of the above powders, for example, an appropriate amount of balsam, screen oil, etc. may be added.

In the first aspect of the present invention, first, the paste is applied to ceramics and then heated in an oxidizing atmosphere to bake the paste onto the ceramics. The coating thickness of the paste may be approximately 5 to 30 μm. No special atmosphere is required as an oxidizing atmosphere;
Air, a mixture of air and nitrogen, etc. may be used. Heating conditions may vary depending on the shape and dimensions of the ceramic, the composition of the paste, the amount of application, etc., but are usually 1100~
It may be heated at about 1300℃ for about 5 to 20 minutes. In the coating layer baked by heating, a portion of the oxide melt permeates into the ceramic and is firmly bonded to the ceramic, and also has excellent uniformity and smoothness.

After forming the baked layer on the ceramic as described above, silver solder is placed on the baked layer, and the metal member to be joined is placed on the silver solder, and then heated for 600 minutes in a reducing atmosphere. Heat treatment at ~900℃.
Through this heat treatment, the baked layer is reduced and metalized, and at the same time, the metal component is firmly bonded to the baked layer via the silver solder, thereby achieving a strong bond between the ceramic and the metal component in a very simple method. be able to.

The reducing atmosphere may be, for example, a hydrogen atmosphere, a carbon monoxide atmosphere, or the like. Heating time is usually 5~
It should be about 30 minutes. Any commonly known composition of silver solder can be used, and a suitable one may be used depending on the type of metal members to be joined. An example of the composition of silver solder is one consisting of 72% silver and 28% copper (weight ratio). The amount of silver solder processed is not particularly limited,
The processing amount may be the same as that in normal brazing, for example, about 1 to 2 mg/cm ² .

In the second invention of the present application, after forming a baked layer on the ceramics in the same manner as the first invention of the present application, silver solder is placed on the baked layer, and then thermal expansion is applied between the metal member to be joined and the ceramics. After arranging an intermediate material having a certain ratio and further arranging a silver solder thereon, a metal member to be joined is placed on top of the silver solder. This was then heated for 600 min in a reducing atmosphere.
Heat treatment is performed at ~900°C to reduce and metalize the baked layer, and at the same time, the baked layer and the intermediate material, and the intermediate material and the metal member are firmly joined via silver solder. When ceramics and metal members are joined by such a method with an intermediate material present between the ceramics and the metal member, the resulting joined body will be able to maintain the bond between the ceramic and the metal member even when used at high temperatures. The difference in coefficient of thermal expansion between the two is alleviated by the intermediate material, resulting in extremely excellent heat resistance.

As the intermediate material, it is sufficient to use a metal that is firmly joined by silver solder and whose coefficient of thermal expansion is between that of the metal member to be joined and the ceramic, and is preferably a metal whose coefficient of thermal expansion is between the two. Preferably something close to the value. As such intermediate materials,
It may be selected as appropriate depending on the type of metal and ceramics to be joined, but as an example, Fe-Ni- Co
Examples include alloys, Fe-Ni-Cr alloys, and the like. As the thickness of the intermediate material increases, the effect of alleviating the difference in coefficient of thermal expansion becomes greater, but a thickness of about 1 to 2 mm can normally exhibit sufficient effects.

The type and amount of paste used to form the baked layer,
The baking conditions for the paste, the type and amount of silver solder, etc.
It may be the same as the first invention of the present application.

Effects of the Invention According to the method of the first invention of the present application, a metal member can be bonded to ceramics with a simple operation, and a bonded body having excellent bonding strength, heat resistance, etc. can be obtained. Moreover, since it is a very simple method, uniform bonding can be easily performed without requiring any skill.

According to the method of the second invention of the present application, a bonded body with excellent bonding strength, uniformity of quality, etc., and furthermore, extremely good heat resistance can be obtained by a simple method.

Examples Hereinafter, the present invention will be explained in detail with reference to Examples.

Example 1 Alumina ceramics containing 96% Al ₂ O ₃ (20×
20 x 4 mm), a paste consisting of 100 parts by weight of a mixture consisting of 75% by weight of NiO, 20% by weight of Cu ₂ O and ₂ % by weight of SiO, and 100 parts by weight of screen oil.
Coated to a thickness of 10-30 μm and heated at 1180 °C in air for 10
The paste was baked into ceramics by heat treatment for a minute. Next, 15 x 15 x 0.2 mm silver solder (72% silver, 28% copper) and mild steel were sequentially layered on the baked layer, and in a hydrogen gas atmosphere,
Heat treatment was performed at 760-840°C for 10 minutes. As a result, the mild steel was firmly bonded onto the ceramic, and its shear strength was 5 to 10 kg/mm ² .

Example 2 After forming a baked layer on alumina ceramics in the same manner as in Example 1, a 15 x 15 x 0.2 mm silver solder (72% silver, 28% copper), 12 x 12 x 2 mm
Kovar (Fe-Ni-Co alloy), 15×15×0.2mm
After sequentially layering silver solder and mild steel on the baked layer, heat treatment was performed at 760 to 840°C for 10 minutes in a hydrogen gas atmosphere. As a result, the mild steel was firmly bonded to the ceramic, resulting in a bonded body with extremely high heat resistance.

Claims (1)

[Claims] 1 A paste containing NiO and Cu ₂ O and/or SiO ₂ is applied onto ceramics, baked in an oxidizing atmosphere, and then silver solder is placed on the baked layer, and this A method for joining ceramics and metal, which comprises placing a metal to be joined on top and heat-treating the metal at 600 to 900°C in a reducing atmosphere. 2 After applying a paste containing NiO, Cu ₂ O and/or SiO ₂ onto ceramics and baking it in an oxidizing atmosphere, silver solder, intermediate material, silver solder and metal to be joined are placed on the baked layer. A method for joining ceramics and metal, characterized by sequentially arranging them and heat-treating them at 600 to 900°C in a reducing atmosphere.