JP5289218B2 - Manufacturing method of ceramic sintered body - Google Patents

Description

The present invention relates to a method for manufacturing a ceramic sintered body in which ceramic unsintered compacts are brought into contact with each other to form a joined body, and then sintered and integrated.

Conventionally, ceramic bonding technology has been proposed, but with the recent increase in size of liquid crystal panels, ceramic parts used in equipment for manufacturing the liquid crystal panel have also increased in size. ing. If a joining technique is used, it is possible to reduce the weight because a hollow structure can be obtained even if it is large. The following is disclosed as a joining technique.

For example, Patent Document 1 discloses a ceramic member in which a plurality of generation shapes of ceramic members are formed, the plurality of generation shapes are bonded with a slurry made of the same raw material as the generation shapes, and then the plurality of generation shapes are sintered. In this joining method, there is disclosed a joining method for ceramic members, characterized in that the plurality of generated shapes are impregnated with water and then adhered with a slurry made of the same raw material as the generated shapes.

In Patent Document 2, an adhesion-inducing liquid having a property of dissolving or swelling the binder is applied to the surface of a substrate molded body obtained by molding a kneaded material containing ceramic powder and a binder into a predetermined shape. A pressure-sensitive adhesive layer forming step for forming a pressure-sensitive adhesive layer, and bringing the object to be bonded into contact with the surface in that state, thereby bonding the substrate molded body and the material to be bonded to each other via the pressure-sensitive adhesive layer. Prior to the application of the adhesion-inducing liquid, a portion of the surface of the substrate molded body that is not desired to be bonded to the object to be bonded is applied to the adhesion-inducing liquid. A bonding blocking layer forming step for forming a bonding blocking layer made of an insoluble or hardly soluble material in advance; and a firing step for baking the bonded body. In By blocked by the bonding blocking layer serial and binder contact with the adhesive-induced liquid, method for manufacturing a ceramic structure, characterized in that as the adhesive layer is not formed is disclosed.

Japanese Patent Application Laid-Open No. 06-191959 JP-A-10-166343

However, as in the invention described in Patent Document 1, in the method of bonding a molded body and a molded body via a slurry, due to the difference in shrinkage between the molded body and the slurry during drying and sintering. In some cases, adhesion failure occurred, and a gap was formed in the sintered body.

Moreover, in the invention described in Patent Document 2, the adhesive layer produced by the dissolution or swelling of the binder may cause adhesion failure similarly to the above-mentioned mud, and may cause a gap in the sintered body.

The present invention has been made in view of these problems, and in a method for sintering and integrating a joined body of an unsintered ceramic molded body, a method for producing a ceramic sintered body having no gap in a joint portion is provided. It is to provide.

In order to solve these problems, the present invention provides the following inventions (1) to (6).
(1) a step of preparing a ceramic molded body including a ceramic powder and a binder;
A step of forming a dispersion layer by dispersing ceramic powder and a binder by containing only water on a bonding surface of the ceramic molded body; and
A step of abutting the bonding surfaces on which the dispersion layer is formed to obtain an unsintered bonded body;
Sintering and integrating the unsintered joined body;
Only including,
Concavities and convexities are formed on the bonding surface of the ceramic molded body, the height of the concavities and convexities is 5 to 100 μm, and the spacing between the irregularities is 0.05 to 1.0 mm.
The ceramic molded body is composed of 50.3 to 94.7% by volume of the ceramic powder, 0.8 to 7.5% by volume of the dispersant, 3.8 to 17.4% by volume of the binder, and 0. The manufacturing method of the ceramic sintered compact containing 8-24.8 volume% .
(2) The method for producing a ceramic sintered body according to (1) , wherein the step of obtaining the unsintered joined body joins the joined surfaces together while excluding a part of the dispersion layer from the joined surface.
(3) The method for producing a ceramic sintered body according to (1) or (2) , wherein the ceramic molded body includes an acrylic emulsion binder, and water to be included in the joint surface is alkaline.
(4) The method for producing a ceramic sintered body according to any one of (1) to (3), wherein the ceramic formed body is obtained by casting.

In the method of sintering and integrating the joined body of unsintered ceramic molded bodies, a ceramic sintered body having no gap at the joint can be obtained.

It is an expanded sectional view of the joined surface of a ceramic compact. Production No. It is a microscope picture of 1 junction part. Production No. It is a microscope picture of 10 junction parts.

Hereinafter, the invention will be described in more detail. The present invention includes a step of preparing a ceramic molded body including ceramic powder and a binder, a step of forming a dispersion layer by dispersing the ceramic powder and the binder by adding water to the bonding surface of the ceramic molded body, Manufacturing a ceramic sintered body comprising: a step of abutting the joining surfaces on which the dispersion layers are formed to obtain an unsintered joined body; and a step of sintering and integrating the unsintered joined body Is the method.

By forming the dispersion layer by dispersing ceramic powder and binder with water on the joint surface of the ceramic molded body, the adhesion between the molded bodies is increased, and it is possible to obtain an integrated sintered body without gaps. It becomes. In addition, the “integrated” ceramic sintered body of the present invention has extremely high adhesion, and no gap is observed in the penetration flaw detection test.

It is preferable that irregularities are formed on the joint surface of the ceramic molded body. When the bonding surface has irregularities, it becomes easy to disperse the ceramic powder and the binder by containing water . FIG. 1 is an enlarged cross-sectional view of a bonding surface 1 of a ceramic molded body. Convex portions 2 are formed on the joint surface, and irregularities are formed by the continuation of the convex portions 2. The convex part 2 has the top part 2a and the bottom part 2b. The unevenness of the joint surface is formed in a predetermined range with respect to the height H of the unevenness, that is, the height from the bottom 2b to the top 2a and the interval L between the unevenness, that is, the distance between adjacent tops.

About the range, it is preferable that the height of the unevenness | corrugation of a joint surface is 5-100 micrometers, and the space | interval of an unevenness | corrugation is 0.05-1.0 mm. By appropriately controlling the height and interval of the unevenness, the formation of the dispersion layer can be homogenized and the adhesion can be enhanced. More preferably, the height of the unevenness of the joint surface is 10 to 50 μm, and the interval between the unevenness is 0.1 to 1.0 mm, the height of the unevenness is 20 to 40 μm, and the interval of the unevenness is 0.2 to 0.8 mm. More preferably. In addition, it is most preferable to join the joint surfaces having the same unevenness, but the present invention is not limited to this, and bonding is possible even if the uneven shape of the joint surface is different as long as it is within the above range. . In addition, the uneven | corrugated height and the uneven | corrugated space | interval measured the sample 10 places or more with the surface roughness measuring apparatus (measurement length: 4 mm), and computed the average.

The unevenness of the joint surface can be formed by a known method such as face milling using a milling machine. A predetermined uneven shape can be formed by using a predetermined milling blade according to the shape of the unevenness and controlling the cutting amount, the feed rate, and the like.

The dispersion layer is formed by adding water to the joint surface of the molded body. As a method of including water , a method of applying to the molded body or a method of immersing the molded body can be employed. The thickness of the dispersion layer is preferably formed in a range of 0.5 to 10 times the height of the unevenness. If it is such a range, it can join by a homogeneous dispersion layer resulting from the uneven | corrugated shape. A more preferable range is 0.5 to 2 times.

About a some molded object, after forming a dispersion layer in the joining surface, each joining surface is faced | matched and an unsintered joined body is obtained. At this time, it is possible to abut the joining surfaces while excluding a part of the dispersion layer from the joining surface. By eliminating the excessive dispersion layer, it is possible to avoid the formation of a portion with significantly different solid content or binder amount at the joint. As described above, the unevenness of the joint surface is formed in a predetermined shape and the dispersion layer is homogenized, so that part of the dispersion layer is evenly eliminated. It is possible to obtain a sintered body that does not exist.

When the molded bodies are brought together, a load may be applied as necessary so that a part of the dispersion layer is excluded from the joint surface. Further, in order to promote the removal of the dispersion layer, the joining surfaces may be rubbed together.

Ceramic compacts prepared for joining include ceramic powder 50.3-94.7% by volume, dispersant 0.8-7.5% by volume, binder 3.8-17.4% by volume, moisture 0.8- 24.8% by volume is included. By using such a molded body, it becomes easy to form a dispersion layer when moisture is included. Further, by setting the amount of ceramic powder within the above range, the thickness of the dispersion layer can be controlled, and the shape of the compact itself can be maintained. Similarly, the amount of the binder is preferably within the above range in order to maintain the thickness of the dispersion layer and the shape of the molded body. In particular, a large amount of the binder is not preferable because a gap is likely to be generated at the joint. The binder amount is more preferably 5.0 to 13.5% by volume. The dispersant is preferably in the above range in order to increase the dispersion in the dispersion layer. Regarding moisture, if the amount exceeds the above range, an excessive dispersion layer will be formed when moisture is included, or the molded product will not be able to retain its shape. The layer cannot be formed uniformly, which is not preferable. If the configuration of the molded body is in the above range, the dispersion layer can be formed while maintaining the shape of the molded body.

Various ceramics such as oxides such as alumina, magnesia, spinel, zirconia and yttria, carbides such as silicon carbide and titanium carbide, and nitrides such as silicon nitride and aluminum nitride can be applied as the ceramic powder. It is also possible to include a mixture using a plurality of these, or, if necessary, other components such as a sintering aid. Commercially available ceramic powder can be used for these. The ceramic powder preferably has an average particle size of 0.1 to 2.0 μm.

The binder is not particularly limited, and polyvinyl alcohol or acrylic emulsion can be used. Since it is necessary to disperse the binder when water is contained in the joint surface, pH adjustment or the like may be performed as necessary. For example, when an acrylic emulsion is used as a binder, it is preferable to adjust the water contained in the bonding surface to be alkaline. Moreover, as a dispersing agent, well-known things, such as ammonium polycarboxylate, can be used.

The ceramic molded body is preferably formed by casting. This is because the amount of ceramic powder and the amount of binder can be adjusted to the above ranges in the case of a ceramic molded body by casting, and is suitable for the present manufacturing method. Casting molding involves casting a slurry in which ceramic powder is dispersed in a mold made of a water-absorbing material, and the ceramic powder is deposited on the mold simultaneously with the absorption of moisture in the slurry, resulting in a molded product. Is the method. Therefore, adding and dispersing moisture in the ceramic molded body means that the ceramic powder and the binder are redispersed.

Hereinafter, the present invention will be described with reference to examples and comparative examples.

A plurality of plate-shaped ceramic molded bodies (500 × 250 mm, thickness 20 mm) each having a predetermined composition were prepared. About one surface (500x250mm) of plate shape, the face mill process was performed and the predetermined unevenness | corrugation was formed. About each molded object, it dried so that a water | moisture content might become a predetermined value, Then, it joined. The obtained unsintered joined body was fired at 1500 to 1600 ° C. in the air.

As a representative example, test no. 1 will be described below. As a slurry for casting, a commercially available alumina powder (average particle size 0.55 μm, purity 99.7%) was used as a ceramic powder, and 77.1% by mass of alumina powder and a binder (Duramax B manufactured by Nisshin Kasei Co., Ltd.) -1070) 4% by mass, 1.9% by mass of a dispersant (ammonium polycarboxylate), and 17% by mass of ion-exchanged water were blended to prepare a slurry in which alumina powder was dispersed.

Using a mold made of gypsum of a box-type water-absorbing material (inner dimensions; width 700 mm, depth 700 mm, height 40 mm), the slurry was cast from a casting port and was made to fill to obtain a molded body. The molded body was dried until the water content was 6.5% by volume. The joint surface of the molded body was processed by face milling using a milling machine. Concavities and convexities were formed on the joint surface of the obtained molded body, the height of the concavities and convexities was 30 μm, and the spacing between the irregularities was 0.4 mm.

Subsequently, an alkaline aqueous solution (5% by mass ammonia water) was applied to the joint surface to form a dispersion layer. Then, the joining surfaces on which the dispersion layer was formed were slid together and joined together while removing the dispersion layer from the joining surface to obtain an unsintered joined body.

The joined body was sintered at 1600 ° C. in the air. The obtained sintered body was cut, and a penetration inspection test was performed on the joint. In the penetrant flaw detection test, a red check solution (manufactured by Eishin Chemical Co., Ltd.) was sprayed and wiped off 5 minutes later to examine the presence or absence of exudation from the gap. As a result, no gap was observed. A photomicrograph of the joint is shown in FIG. The arrow in FIG. 2 shows a junction part.

Table 1 shows a list of test results. As a result of the flaw detection test, a case where there was no gap was indicated as ◯, and a case where there was a gap was indicated as x. In addition, the average particle diameter of ceramic powder used the laser diffraction type particle size distribution measuring apparatus (LA-920 by Horiba, Ltd.). The joint surface shape was measured using a surface roughness measuring device (SV-3000C manufactured by Mitutoyo Corporation). The amount of ceramic powder, the amount of dispersant, the amount of binder, and the amount of water contained in the compact were measured by their specific gravity and pyrolysis GC-MS.

Production No. In 1 to 5, no gap was found as a result of the flaw detection test. On the other hand, Production No. In 6-13, a gap occurred. Production No. A photomicrograph of 10 joints is shown in FIG.

1 Molded body 2 Convex part 2a Top part 2b Bottom part

Claims (4)

Preparing a ceramic molded body containing ceramic powder and a binder;
A step of forming a dispersion layer by dispersing ceramic powder and a binder by containing only water on a bonding surface of the ceramic molded body; and
A step of abutting the bonding surfaces on which the dispersion layer is formed to obtain an unsintered bonded body;
Sintering and integrating the unsintered joined body;
Only including,
Concavities and convexities are formed on the bonding surface of the ceramic molded body, the height of the concavities and convexities is 5 to 100 μm, and the spacing between the irregularities is 0.05 to 1.0 mm.
The ceramic molded body is composed of 50.3 to 94.7% by volume of the ceramic powder, 0.8 to 7.5% by volume of the dispersant, 3.8 to 17.4% by volume of the binder, and 0. The manufacturing method of the ceramic sintered compact containing 8-24.8 volume% . The method for producing a ceramic sintered body according to claim 1 , wherein the step of obtaining the unsintered bonded body causes the bonded surfaces to abut each other while excluding a part of the dispersion layer from the bonded surface. The method for producing a ceramic sintered body according to claim 1 , wherein the ceramic molded body includes an acrylic emulsion binder, and water included in the bonding surface is alkaline. The said ceramic molded object is a manufacturing method of the ceramic sintered compact as described in any one of Claims 1-3 obtained by casting molding.