JPH09157038A - Setter for firing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a setter having good heat resistance, being in point contact with a body to be fired since the surface thereof is roughened by blasting treatment, and capable of easily recoverying the fired body without causing adhesion between the setter and the body even when firing temp. is high and without peeling-off the stuck materials even at the time of repeatedly using the setter since there is no stuck material on the surface thereof. SOLUTION: The contact surface of this setter with bodies to be fired is subjected to blasting treatment by using a projectile material. As the projectile material, a material having an average particle size that is >=0.025mm and also smaller than the maximum dimensional length of the surface in contact with the setter of each of the bodies to be fired, is used. Further, the material of the setter is a ceramic material consisting of zirconia, alumina, magnesia, silica, zircon, mullite, silicon nitride, silicon carbide, or the like, or a combination thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a setter used for firing electronic material parts and the like.

[0002]

2. Description of the Related Art Multilayer capacitors, ceramic capacitors including high voltage capacitors, piezoelectric materials such as piezoelectric ceramics, microwave dielectrics, multilayer LC composite chips, S
High frequency components such as AW filters, semiconductor capacitors, P
Barium titanate (BaTiO ₃ ), lead zirconate titanate (PbZrTiO ₃ ), strontium titanate (SrTiO ₃ ), zinc oxide (ZnO), as a raw material for semiconductor ceramics such as TC thermistor, NTC thermistor, ceramic varistor, and ceramic sensor. Zirconium oxide (ZrO ₂ ), rare earth oxides, oxides such as glass materials, or their composites are used.

Such electronic components are generally prepared by mixing these raw materials, molding them, and placing them on a setter for firing.
By firing at ˜1400 ° C., a ceramic body is formed, and electrodes are formed on this body to form an element, which is finally assembled into a component.

[0004]

When firing electronic material parts such as these various capacitors and sensors, oxide-based setters such as alumina, mullite and zirconia are generally used. However, Ba of BaTiO ₃ and Pb of PbZrTiO ₃ which are the main raw materials of the capacitor react with alumina and are contaminated, and the electrical characteristics are deteriorated, and a fired product containing a large amount of glass components is fired near the melting temperature of glass. In this case, there was a problem that the glass component was melted and the setter and the fired product adhered to each other.

Therefore, in order to prevent the reaction or adhesion of the burned material with the setter, a method is used in which ceramic powder that does not react with the burned material is spread on the setter as spread powder and fired. However, even in this method, since the ceramic powder adheres to the surface of the fired product, the work of removing the powder occurs. Further, when the firing temperature becomes high, the powder particles agglomerate or adhere and agglomerate, which makes it difficult to reuse the powder as a floor powder, and it is necessary to treat it as industrial waste.

Recently, miniaturization and weight reduction of AV equipment, OA equipment, home electric appliances, etc., in which capacitors and the like are frequently used, are required, and electronic material parts are also miniaturized. Contamination of the fired product due to contact between the two and generation of defective products due to adhesion between the fired product and the setter are important problems including the treatment of industrial waste.

As a method for solving these problems, a high-purity ceramic that does not react with the fired product is selected on the firing setter, and this is sprayed, or a substance that does not react with the fired product is used. However, the problem of adhesion of the setter to the fired product remains as the firing temperature becomes higher.

Further, a method of laying a spherical ceramics sintered body on a setter as spread powder and firing, or a method of adhering the spherical ceramics sintered body onto the setter is effective. If the size of the sintered spheres used as the spread powder is large, it takes time to collect the fired product.In the case of the spread powder, if the top surface of the setter is not concave, the spread powder will spill or if the sintered spheres are bonded If the force is weak, repeated use causes a problem such as separation of the sintered sphere from the setter.

In the present invention, these problems have been solved, the heat resistance is good, and the surface of the setter is roughened by blasting, so the fired product and the setter are in point contact, and the firing temperature becomes high. Also, since the burned material and the setter do not adhere to each other and there is no adhesive on the surface of the setter, these adhesives do not peel off even after repeated use, and the burned material can be easily collected. It is intended to provide setters.

[0010]

DISCLOSURE OF THE INVENTION The gist of the present invention is a setter for firing, characterized in that the contact surface with the fired material is blasted with a shot material.

The requirements to be satisfied by the firing setter of the present invention will be described in detail below.

(A) Projection method As a method for projecting a projection material, there are an injection blast method using compressed air and a projection blast method using a mechanism of centrifugal force action. As a method of blasting the surface of the setter that comes into contact with the fired product, the jet blast method is suitable because of the size of the shot material. The jet blast method includes a suction method typified by a gravity blast that drops the shot material by gravity and a siphon blast that uses the action of a siphon, and a direct pressure method that pressure-feeds the shot material. When processing the firing setter in the state of the molded body, it is preferable to use the suction method, and when processing in the state of the sintered body, it is preferable to use the direct pressure method capable of strong blasting.

The processing accuracy given to the setter surface varies depending on the projection conditions such as the air pressure, the projection distance, the projection angle, the projection time, and the nozzle diameter.
It is necessary to select an appropriate arc height value using an Almen gauge and Almen strip, and project the machined surface in a state close to full coverage.

(B) Shape of Shot Material The shape of the shot material is roughly classified into a grit having a crushed surface and a ridge angle, and a spherical shot. When the firing setter is processed in the state of a molded body, either grit or shot may be used, but when it is processed in the state of a sintered body, it is preferable to use grit having a high grinding force.

Since the processing accuracy given to the setter surface also varies depending on the shape of the shot material, the Almen gauge and the Almen gauge can be adjusted according to the type of setter, depending on the projection conditions such as air pressure, projection distance, projection angle, projection time, and nozzle diameter. It is necessary to select an appropriate arc height value using a strip and project the processed surface in a state close to full coverage. (C) Material of shot material As the shot material, there are iron-based shot materials such as carbon steel, stainless steel, and cast iron, and non-ferrous shot materials such as zinc, aluminum, and copper. As projectiles, glass projectiles such as soda lime, ceramics projectiles such as alumina, zirconia, zircon, silicon carbide and mullite, thermoplastic resin projectiles such as polyester and nylon, thermosetting resins such as urea, melamine and ferrules There are plant-based shot materials such as shot materials, corn, nuts, and walnuts. When the surface of the firing setter is blasted, it is preferable to use a non-metal blast material because of the problem of surface contamination.

When the firing setter is processed in the form of a molded product, it is not necessary to limit it as long as it is a non-metal projection material, but when the molded product is thin, it is easily broken, so glass or resin is used. It is preferable to use a soft shot material such as a plant. When working in the state of a sintered body, it is preferable to use a ceramics projection material having hardness such as silicon carbide.

The processing accuracy given to the setter surface varies depending on the material of the shot material. Therefore, according to the form of the setter, depending on the projection conditions such as air pressure, projection distance, projection angle, projection time, nozzle diameter, etc. It is necessary to select an appropriate arc height value using a strip and project the processed surface in a state close to full coverage. (D) Particle size of shot material The "average particle size" of the shot material means that the average particle size is measured by the test method based on JIS R 6002, and the value is larger than 0.025 mm and the fired product is Should be in a range smaller than the maximum value of the length of the surface in contact with the setter. If a shot material larger than this value is used, the roughness (unevenness) of the upper surface of the setter is larger than that of the fired product, and the effect of point contact between the fired product and the setter is reduced.

On the other hand, when the projection material having a small particle size is used for the projection, the point contact effect is obtained. However, if the projection material is too small, the roughness of the upper surface of the setter becomes close to a flat surface, so that the point contact effect is lost. In particular, a surface projected with a projection material smaller than 0.025 mm is comparable to a flat surface, and thus the higher the baking temperature, the more likely the baked product and the setter are to adhere to each other.

Since the processing accuracy given to the setter surface varies depending on the particle size and distribution of the shot material, air pressure, projection distance, projection angle, projection time,
Select an appropriate arc height value using an Almen gauge and Almen strip according to the projection conditions such as the nozzle diameter.
It is necessary to project the processed surface in a state close to full coverage.

(E) Coverage As a method of indicating the processed state of the surface, there is coverage. This is the total processing area A and A into Almen strip.
B / A x 100 from the total B of the indentation areas included in
(%), And 98% or more is expressed as full coverage.

If this value is less than 80%, there is a high possibility that the flat product remaining on the surface of the baking setter will adhere to the baked product.

(F) Material of Setter The material of the fired setter is generally zirconia, alumina, magnesia, silica, zircon, mullite, ceramics such as silicon nitride or silicon carbide, or a composite thereof.

These setters are used properly according to the material of the fired product, the firing temperature, the price, and the like.

The firing setter of the present invention has a setter surface roughened by blasting regardless of these materials.

A method for manufacturing a zirconia-based setter, which is an example of the firing setter of the present invention, will be described below.

The zirconia powder used for the zirconia-based setter is manufactured by electrofusion method, hydrolysis method, neutralization coprecipitation method,
The hydrolysis-neutralization method, the hydrothermal oxidation method, the thermal decomposition method, the alkoxide method, and the like can be used, but they are not particularly limited. Further, rare earth oxides such as MgO, CaO, Y ₂ O ₃ and CeO ₂ are often used as stabilizers, but when used as a setter, they should be thermally and mechanically stable, There is no particular need to limit the stabilizer. For example, Y ₂
If it is O ₃ , the molar ratio of Y ₂ O ₃ / ZrO ₂ is 1.5 / 9.
It is preferably 8.5 or more. If it is less than 1.5 / 98.5, the amount of monoclinic zirconia is large, and it becomes a setter having weak thermal shock resistance due to the transition, and cannot be reused.

In addition to the stabilizer and the unavoidable components,
In order to improve heat resistance and mechanical strength, Al ₂ O ₃ , Ti
An oxide such as O ₂ or SiO ₂ or a compound thereof may coexist. There is no need to limit the content unless it reacts with or adheres to the fired product during firing, but it is preferably used within the range of 0.05 to 30 mass% with respect to the total of zirconia and the stabilizer. This is because if the amount is more than 30% by mass, the original properties of zirconia deteriorate, such as the toughness decreases.

As the powder molding method, there are molding methods such as compression molding in which the powder is molded using a mold, and casting molding in which the slurry is poured into a mold, but it is not necessary to limit the manufacturing method. Since the characteristics differ depending on the powder manufacturing method, it is necessary to select a molding method suitable for the characteristics of the powder as the raw material.

The zirconia-based setter used in the present invention is obtained, for example, by adding yttria powder, which is a stabilizer, to zirconia powder containing no stabilizer in an amount of 5% by mass based on zirconia, and pulverizing and mixing the mixture in a wet manner. Obtain a slurry.
The viscosity of the obtained slurry is adjusted to 1000 cP with a thickener, and the resulting slurry is dried and granulated in the air using a rotary disk type spray dryer to obtain a zirconia-based powder. The obtained powder is put into a mold and compression-molded to obtain a molded body. The surface of this molded body was blasted to a coverage of 80% or more by using plastic beads, and then, by a firing furnace in the atmosphere,
It is obtained by a method of firing at 1300 to 1600 ° C.

The sintering density of the firing setter is preferably 70% or more of the theoretical density, except for those having fibers mixed therein or those having a porous shape. If it is less than 70%, the thermal or mechanical properties of the setter will be poor. Preferably, the theoretical density is 80% or more.

[0031]

As described above, since the setter for firing of the present invention has good heat resistance and the surface of the setter is roughened by blasting, the fired product and the setter are in point contact, and the firing temperature is high. However, since the fired product and the setter do not adhere to each other and there is no adherent on the surface of the setter, the adhered product does not peel off even after repeated use, and the fired product can be easily collected.

By using this setter, even if a fired product containing many glass components is fired at a temperature close to the melting temperature of glass, the fired product and the setter do not adhere to each other, and the fired product can be easily collected. Also, since no bedding powder is used, there is no problem of industrial waste.

By using this firing setter, it is possible to meet strict requirements regarding manufacturing conditions, such as prevention of adhesion to the setter due to miniaturization of the fired product or prevention of adhesion due to higher firing temperature.

[0034]

The present invention will be described below in more detail with reference to examples and comparative examples.

Example 1 300 g of TZ-3Y (spray-dried product), a commercially available zirconia powder manufactured by Tosoh Corp., was placed in a mold having a size of 180 mm × 180 mm and press-molded at a pressure of 300 kg / cm ^{2 to} obtain a molded body. Got The surface of the obtained molded product is a commercially available zirconia shot material, TZ-BS-90 (manufactured by Tosoh Corporation:
Spherical, 0.075-0.106mm) and Osawa &
Using a company Wonder Gun (W301ES-22 type: injection nozzle inner diameter 6 mmφ), air pressure 3 kg / c
Blasting was performed at m ² G, a projection angle of 60 °, and a projection distance of 10 cm, and the zirconia-based setter (sintering density: 150 mm, fired at 1500 ° C. for 4 hours in an electric furnace in an air atmosphere). × 150mm × thickness 3m
m). On this setter, 10 moldings made of barium titanate and having a contact surface of length 2 mm × 1 mm were placed,
In an air atmosphere, it was fired in an electric furnace under conditions of 1330 ° C. and a holding time of 2 hours.

Example 2 The surface of the molded body obtained in Example 1 was a commercially available zircon shot material, Zirblast B30 (SEPR: spherical, 0.425 to 0.45).
0.600 mm) and blasting under the same conditions as in Example 1, and 1500 in an electric furnace in the atmosphere.
Firing was performed under the conditions of a temperature of 4 ° C. and a holding time of 4 hours to obtain a zirconia-based setter (150 mm × 150 mm × thickness 3 mm) having a sintered density of 98.5%. On this setter, 10 moldings having a bonding surface of barium titanate and having a length of 2 mm × 1 mm were placed and held at 1330 ° C. by an electric furnace in the air atmosphere.
It was fired under the condition of time.

Example 3 The surface of the molded body obtained in Example 1 was a commercially available zirconia projection material, TZ-GS # 80 (manufactured by Tosoh Corporation: grit-like,
0.125 to 0.350 mm) and blasted under the same conditions as in Example 1, and fired in an electric furnace in an air atmosphere at 1500 ° C. for a holding time of 4 hours to obtain a sintered density of 98.5%. Zirconia Setter (150mm × 15
0 mm × thickness 3 mm) was obtained. On this setter, ten compacts having a contact surface length of 2 mm × 1 mm made of barium titanate were placed, and 133 were formed by an electric furnace in an air atmosphere.
Firing was performed under the conditions of 0 ° C. and holding for 2 hours.

Example 4 The surface of the molded body obtained in Example 1 was a commercially available glass projection material, Unibeads UB-79L (manufactured by Union Corporation: spherical, 0.1
06-0.150 mm), and air pressure 4 kg / c
Blasted under the same conditions as in Example 1 except for m ² G,
The zirconia-based setter (150 mm × 150 mm × thickness 3 mm) having a sintering density of 98.5% was obtained by firing in an electric furnace under an atmosphere of 1500 ° C. for 4 hours. On this setter, ten compacts each having a contact surface of barium titanate and having a length of 2 mm × 1 mm were placed, and fired at 1330 ° C. for 2 hours in an electric furnace in the atmosphere.

Example 5 The surface of the molded body obtained in Example 1 was a commercially available melamine resin blast material, PLASHOT TPS # 30 (manufactured by Toshiba Ballotini Co., Ltd .: grit-like, 0.600 to 0.850 mm).
Example 4 except that the air pressure was 5 kg / cm ² G
Blasting under the same conditions as above, and firing in an electric furnace in an air atmosphere at 1500 ° C. for a holding time of 4 hours.
50 mm × thickness 3 mm) was obtained. On this setter, 10 compacts each having a contact surface length of 2 mm × 1 mm made of barium titanate were placed, and the molded product was heated to 13
Firing was performed under the conditions of 30 ° C. and a holding time of 2 hours.

Example 6 The molded body obtained in Example 1 was placed in an air furnace under an air atmosphere,
Sintered at a density of 9 after firing at 1500 ° C for 4 hours
8.5% zirconia setter (150 mm x 150
mm × thickness 3 mm) was obtained. The surface of this setter is a commercially available silicon carbide shot material, Fuji Random C # 46 (manufactured by Fuji Manufacturing Co., Ltd .: grit shape: 0.106 to 0.150 mm).
Was used for blasting under the same conditions as in Example 5. On this setter, ten compacts each having a contact surface of barium titanate and having a length of 2 mm × 1 mm were placed, and fired at 1330 ° C. for 2 hours in an electric furnace in the atmosphere.

Comparative Example 1 200 g of a commercially available zirconia powder TZ-3Y (spray dried product) manufactured by Tosoh Corp. was put into a mold having a size of 180 mm × 180 mm and press-molded at a pressure of 300 kg / cm ² . The molded body is heated to 150 ° C. by an electric furnace in an air atmosphere.
Sintered density is 98.5% after firing at 0 ° C for 4 hours
Flat plate zirconia setter (150mm × 150
mm × thickness 2 mm) was obtained. On this setter, 10 compacts each having a contact surface length of 2 mm × 1 mm and made of barium titanate were placed, and were subjected to 1330 by an electric furnace in an air atmosphere.
Firing was performed under the conditions of ° C and holding for 2 hours.

However, since the setter surface is flat,
A part of the sintered body made of barium titanate was adhered to the setter.

Comparative Example 2 Blasting was carried out under the same conditions as in Example 5 except that the air pressure was 2 kg / cm ² G, and firing was performed in an electric furnace in the atmosphere at 1500 ° C. for a holding time of 4 hours, followed by firing. Zirconia-based setter with a consolidation density of 95.5% (150 mm x 15
0 mm × thickness 3 mm) was obtained. On this setter, ten compacts having a contact surface length of 2 mm × 1 mm made of barium titanate were placed, and 133 were formed by an electric furnace in an air atmosphere.
Firing was performed under the conditions of 0 ° C. and holding for 2 hours.

However, since the roughness of the surface of the setter was close to a flat surface, the sintered body partially made of barium titanate was adhered to the setter.

Comparative Example 3 A blast material is commercially available crushing glass beads, Unibeads UB-
2425L (manufactured by Union Corp .: spherical, 2.00-2.
36 mm), blasting was performed under the same conditions as in Example 4, and 1500 ° C. in an electric furnace in the atmosphere.
Baking under the condition of holding for 4 hours, zirconia-based setter (150 mm x 150 mm x thickness 3 m) with a sintered density of 95.5%
m). On this setter, 10 moldings made of barium titanate and having a contact surface of length 2 mm × 1 mm were placed,
In an air atmosphere, it was fired in an electric furnace under conditions of 1330 ° C. and a holding time of 2 hours.

However, since the roughness of the surface of the setter was large, the sintered body partially composed of barium titanate was adhered to the setter. Moreover, it took time to collect the fired product.

Table 1 shows the characteristics of the setters obtained in Examples 1 to 6 and Comparative Examples 1 to 3 and the results of the firing test.

[0048]

[Table 1]

Claims (5)

[Claims] 1. A firing setter characterized in that a contact surface with a fired product is blasted with a blast material. 2. The blast material according to claim 1, wherein
2. A blast material having a mean particle size (diameter) larger than 5 mm and smaller than the maximum value of the length of the surface where the calcination material contacts the calcination setter is used. Setter. 3. The firing setter according to claim 1, wherein the surface of the firing setter according to claim 1 or 2 is blasted to a coverage of 80% or more. 4. The material of the firing setter according to claim 1, which is zirconia, alumina, magnesia,
The sintering setter according to any one of claims 1 to 3, which is ceramics such as silica, zircon, mullite, silicon nitride or silicon carbide, or a ceramic composed of a composite thereof. 5. A firing method characterized by firing using the firing setter according to claim 1.