JPS58190878A - Manufacture of ceramic bonded body - 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] The present invention relates to a method for joining ceramics.

Ceramics have recently been widely used in everything from general industrial materials to electronic components, and are expected to be used in an even wider range of fields. Along with this, there is a strong need for the development of a method for producing ceramic sintered bodies with complex shapes, and for this purpose, there is a strong desire for a method for bonding ceramics with high strength and a method for bonding different types of ceramics.

Conventional methods for joining ceramics that have been considered include Conventional Method A: A ceramic molded body with a large firing shrinkage rate is fitted with a ceramic molded body with a small firing shrinkage rate, and firing is performed.Conventional Method B: A paste made by mixing ceramic powder and an organic binder of the same composition is applied to the joint surface of the ceramic forming body so as to form the desired dovetail, and then firing is performed.

Conventional method C: Joining of both ceramic sintered bodies to be joined 7i1
Either an Ir metallization is formed and the metallization is joined directly, or the metallization is joined by brazing.

There is something like that.

However, the above conventional method has the following problems.

That is, in the conventional method Δ, it is difficult to process the fitting portion of the formed body and control the firing shrinkage rate, and furthermore, since stress remains in the fitting portion after firing, the bonding strength deteriorates. Furthermore, there is also the problem that the shape required for fitting is limited.

Conventional method B has a simpler manufacturing process than conventional method A, but it is known that the joint strength is inferior because many pores remain in the joint even after firing.

In addition, in conventional method C, the ceramic bonding surface must be finished with extremely high precision (surface roughness l/1 or less).
, is not suitable for mass production, and has the disadvantage that the metal of the ceramic bonding layer melts due to temperature rise, resulting in a corresponding decrease in bonding strength.

The object of the present invention has been made in view of the above circumstances, and is to provide a ceramic bonding method that has high bonding strength and can produce ceramic products with complex shapes.

Another object of the present invention is to fully utilize the characteristics of ceramics, which have high strength under high temperatures, so that it has the advantage that the bonding strength hardly deteriorates until the temperature reaches a temperature at which the material strength of the ceramic base material deteriorates. An object of the present invention is to provide a ceramic bonding method that achieves this.

Still another object of the present invention is to provide a method for manufacturing a ceramic bonded body more easily than conventional bonding methods.

The method for producing a ceramic bonded body of the present invention involves adding an organic binder to ceramic powder, forming the mixture into a desired shape, and heating the bonding surfaces to bond a plurality of formed bodies made of the same or different ceramic materials. It is characterized in that it is crimped by melting and softening, and the resulting main molded joined body is fired.

Hereinafter, the manufacturing method of the present invention will be explained in detail.

In the present invention, a thermoplastic organic substance is mixed into ceramic powder as a binder, and the mixture is molded by any molding method such as injection molding or extrusion molding to obtain a green body. Examples of the thermoplastic organic binder include high-density or low-density polyethylene, polystyrene, polybutylene, polybutadiene, polyvinyl acetate, and polyethylene oxide. In addition, plasticizers such as dibutyl phthalate, di-2-ethylhexyl ester, and diheptyl ester are used to increase meltability and moldability when heated, stearic acid is used to improve mold release, and small amounts of oils and fats (such as wax) are used. It is preferable to add one of both.

The amount of the organic binder added varies depending on the type, particle size, particle shape, etc. of the ceramic powder, and is added as an organic binder to give fluidity to the mixture and enable molding. Although it varies somewhat depending on the type of oil and fat that facilitates degreasing.
1% is appropriate, preferably 35-5 Q vo1%. If the amount of organic binder used is less than 25 vol%, not only will the moldability deteriorate significantly, but also joining will become difficult. In addition, when the amount used is 70 vo/7% or more, the formability and bonding properties are good, but the finished fired product is not only insufficiently sintered, but also has poor density of the ceramic and is not as desired. It is not possible to obtain the same firing shrinkage.

Both surfaces of the plurality of formed bodies made of the same or different ceramic materials thus obtained are heated for as long as possible to melt and plasticize them, and then quickly pressed together.

The pressure that appears in this crimping depends on the type of ceramic powder, particle size,
Although it varies depending on the particle shape and the type of 1141i1 binder, 2 to 20 Kg/am" is appropriate.

If the pressure is less than 2 Kg/oml', many pores remain on the bonding surface, resulting in a decrease in bonding strength. Also, the pressure is 20K
If g/Cn1'' or more, the resulting pressure may deform the formed body or cause cracks on the joint surface.

The above-mentioned pressurization time is usually 10 to 60 seconds, but the larger the bonding area, the longer the pressurization time may be.

The main molded joined body thus obtained is degreased and fired in accordance with the characteristics of the ceramic powder and the binder used to obtain a desired ceramic joined body.

As described above, the method for manufacturing a ceramic bonded body of the present invention can limit the shape and control the firing shrinkage rate as described in the conventional corporation.
problems such as residual stress in the mating part, problems such as deterioration of joint strength due to residual pores in the joint described in conventional method B, and deterioration of joint strength due to finish of ceramic joint surfaces and temperature rise as described in conventional method C. the problem is resolved,
The main ceramic properties can be fully exhibited.

Furthermore, according to the present invention, it is possible to obtain a joined body by simply adding a joining process to the conventional manufacturing process, and there is no need to create a new manufacturing line.
It can also be manufactured at low cost.

Next, the manufacturing method of the present invention and the bonding strength of the ceramic bonded body obtained by the method will be explained using examples.

[Example 1] 18 parts by weight of polystyrene, 2 parts by weight of wax, and 1 part by weight of dihepterester were kneaded with heating to 100 parts by weight of alumina-based ceramic powder, and the mixture was mixed with a diameter of 4 mm.
After granulating it into a spherical shape, it was granulated at 180°C and 140°C as shown in Figure 1.
0Kg/em” 10 x 10 x 100 fl square column 1
was injection molded. Next, both sides 2.3 of this prism to be joined are heated for a short time (3 to 5 seconds) using an infrared lamp.
Heated to around 130℃, and weighed 15kg/2.3 on both sides.
It was established in em'1. By repeating the above steps, a main molded assembly 4 of 1010 x 60 x 100 j1 is created from the five prisms as shown in Fig. 2, heated to 500°C in a furnace, degreased, and fired at 1500°C. Obtain the ceramic bonded body and then remove the ceramic bonded body from the medium heat part.
A disc-shaped test piece 5 of IIM and W size 51111 was produced by cutting. In addition, in FIG. 3, the joint portion is indicated by a dotted line on the test piece 5, this is for ease of understanding.
In reality, it is not something that can be observed (hereinafter, the dotted line in Figure 1 and Figure 4 also shows the same "it taste"). Next, when a leak test was performed on the test piece 5, the degree of leakage was 1O-8Lorr -d
/sao or less, and no air leakage was observed at the junction nr+. Further, as shown in FIG. 4, a 3×4×40-sized bending piece 6 was cut out from the center of the ceramic bonded body and subjected to a J184-point bending test. As a result, the bending strength was 30 Kg/g*2 at 20°C. As a comparative test, a bending strength of a ceramic body of the same shape made from the same ceramic material as above was 31t/m1.
m12 (20°C), and in the same-shaped bending piece obtained by changing only the bonding method to conventional method B according to this example, the bonding surface has more pores than other parts, and the bending strength is 15 Kit.
/min" (20°C). It is known that the bending strength of alumina gradually decreases when the temperature exceeds 800°C, which is a characteristic characteristic of alumina, and the strength of this bonded body was 8o.

The bending strength kKg/m" at 20 degrees Celsius was maintained up to 800 degrees Celsius or above, and the bending strength gradually decreased at temperatures above 800 degrees Celsius. In addition, according to this example, only the bonding method was changed from the conventional method 0. In the case of a bending piece of the same shape, the joining surface of the ceramic sintered body is finished with very high precision (total roughness of 0.5μ or less), and a metallized surface is formed on the joining surface, and the metallized layer is By directly joining these, the transverse bending strength reached the joining strength according to the present invention.

Therefore, compared to the present invention, this process is much more troublesome and is not practical. In addition, in the conventional method 0, it is generally confirmed that if the metallized layer is brazed, the bonding strength is further deteriorated.

[Example 2] After heating and kneading 11 #5 parts by weight of boron carbide, 23 parts by weight of phenol resin, and 23 parts by weight of polystyrene to 100 parts of silicon carbide-based ceramic powder, and granulating the mixture. , injection molded in the same manner as in Example 1, and IOXIOX
A prism of looIIm was obtained.

According to the example, the five prisms were fixed at 110X.
After creating a 50x100 main molded joint and degreasing it,
A ceramic bonded body was obtained by firing at 2150° C. in argon gas. Then, as in Example 1, a leak test and a four-point bending test were conducted, and no air leakage was detected.
", 45Kg/g1vlI was maintained even when the temperature rose to 1200℃. As a comparative test, a ceramic body of the same shape made of the same ceramic material as above had a fractured piece, and the IoI increased to 47Kg/IoI2.1200℃ at 20℃. It was confirmed that the bonding strength hardly deteriorates even in the high temperature range.Furthermore, the same-shaped bending piece obtained by changing only the bonding method to conventional method B according to this example had no resistance. The bending strength was 32 kg/m5y2 (20°C), and it was confirmed that the bonded surface had many pores and a low density.Furthermore, according to this example, only the bonding method was changed to the conventional method (the same shape obtained by tsukikoe). As in Example 1, the ceramic bonding surface of the bending piece was finished with very high precision, so that the bending strength reached the bonding strength of the present invention.

[Example 3] To 100 parts by weight of silicon nitride-based ceramic powder, 40 parts by weight of aluminum oxide and 60 parts by weight of Polymethylenef as a binder were added, and after adjusting the particle size, injection molding was performed in the same manner as in Example 1 to obtain 10XIO× Obtained a 100-maro square pillar.

Furthermore, according to Example 1, the five prisms were fixed at 110X.
A 50×100+ main molded joined body was prepared, degreased, and then fired at 1750° C. in nitrogen gas to obtain a ceramic joined body. When a leak test and a four-point bending test were conducted in the same manner as in Example 1, no air leakage was observed, and the bending strength was 47 Kg/a'' at 20°C. Although it is not the same, the bonding strength is maintained relatively high even at high temperatures, with a strength of 23 kg/g at 1200°C.
It became a%. As a comparative test, a fractured piece of a ceramic body of the same shape made from the same ceramic material as above was 2.
48-7 at 0℃ and 23Kg/- at 211200℃, and even if the temperature rises to 1200℃ like silicon carbide in Example 2, the bonding strength is not maintained as high as at room temperature, but at 1200℃
Relatively high bonding strength was also observed. Incidentally, a bending piece of the same shape obtained by changing only the joining method to conventional method B according to this example had a bending strength of 20 kg/am'' (20°C). In the same shape of the bending piece obtained by using Method C, the ceramic bonding surface was finished with very high precision as in Example 1, and the bending strength of the ceramic joint reached the welding strength according to the present invention.

[Example 4] Alumina ceramic powder (Ala (Ja 90 W)
%, others 8i0s+, (3a(J, MgO2
), 20 parts by weight of polyvinyl chloride and 2 parts by weight of dibutyl phthalate are kneaded while heating,
After granulating the mixture into a spherical shape with a diameter of 4, the mixture was granulated into 6X6X50mm at 175°C and 1450Kg/Cm'' as shown in Figure 5.
The square pillar 7 was injection molded.

In addition, stabilized zirconia powder (Zr (3291wt.

% and other Y2O3), 20 parts by weight of polyvinyl chloride and 2 parts by weight of dibutyl phthalate were kneaded while heating, and a 6 x 6 x 50 fl square column 8 was injection molded in the same manner as above.

Next, each joint surface 9°lO of the prism 7.8 is cleaned with methanol, nitrogen gas heated to 200°C is blown onto the inward direction 9.10 and heated to about 150°C, and at the same time the nitrogen gas is stopped. By fixing at 5 Kg/Cm8, a main molded joined body 11 was obtained as shown in FIG. Then, after degreasing by raising the temperature to 500℃ in a furnace, it is heated to 1600℃.
A ceramic bonded body was obtained by firing the ceramic body.

When the bonded part of the bonded body No. K was observed under a microscope, it was found that there were no pores (Al90s and ZrU$1 were intertwined in a complex structure).
A bending test piece of 1111 was prepared and 1. When the TISA point bending test was conducted, the bending strength was 18Kg/a+'',
It broke on the silconi γ side other than the joint.

As a comparative test, a ceramic body of the same shape made of the same alumina material as above had a bending strength of -'4/
d (20'C), same as before:. , a ceramic body of the same shape made of the same zirconia material as above has a bending strength of 18-/II? r! there were. Further, in the same-shaped bending piece obtained by changing only the joining method to the conventional method B according to this example, an appropriate paste was not found and the joining did not occur. Furthermore, when only the bonding method was changed to conventional method C according to this example, the bonding strength was quite low, less than 1 kg#ll'', because no suitable metal was found.

As is clear from the above-mentioned Examples 1 to 3, the bonding strength of the bonding method of the present invention is dramatically increased, and it goes without saying that the bonding strength can be further increased by increasing the bonding area by adding irregularities to the bonding surface. It is possible to increase Moreover, even when joining different ceramic materials as in Example 4, when alumina and zirconia materials with similar sintering temperature conditions are used, high joint strength is obtained and no fracture occurs at the joint surface in the bending test. The fact that this was not the case is noteworthy because it shows not only the bonding of the same ceramic materials but also the bonding of different ceramic materials.

Furthermore, the bonding method of the present invention has the advantage that a bonded body can be obtained by simply adding a bonding step to the conventional manufacturing process, and can be manufactured at low cost.

[Brief explanation of drawings]

Figure 1 shows an injection molded alumina ceramic molded body, Figure 2 shows an alumina molded joined body, and Figure 3 shows an alumina ceramic molded body.
The figure shows a leak test specimen taken out of an alumina-based joined body, Figure 4 shows a bending test specimen taken out of an alumina-based joined body, and Figure 5 shows an injection-molded alumina-based specimen. FIG. 6 is a diagram showing a ceramic molded body and a zirconia ceramic molded body, and FIG. 6 is a diagram showing an alumina-silconium molded joined body. l...Injection molded alumina ceramic molded body 4...Alumina molded joined body 7...Injection molded alumina ceramic molded body 8...Injection molded zirconia ceramic molded body 11. ...Alumina Φsilcony γ-based molded joint applicant
Kyoto Ceramic Co., Ltd. □□□ School of Law

Claims (2)

[Claims] (1) A method for manufacturing a ceramic bonded body in which a mixture of ceramic powder and an organic binder is molded into a desired shape, and a plurality of the formed bodies are compressed and fired,
A method for manufacturing a ceramic bonded body, characterized in that the bonded surfaces of the formed body are melted and plasticized by heating to be pressure-bonded. (2) The manufacturing method according to claim 181, wherein the ceramic bonded body is formed by bonding a plurality of formed bodies made of the same or different ceramic materials.