JPH1179853A - Setter for baking and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a setter used when an electronic material part or the like is baked. SOLUTION: This setter for baking has a thickness within the range of 0.2-2 mm and has sintered compact density corresponding to >=95% of theoretical density and forms independent through holes on the contact face with baked product. In the setter for baking, one area of through holes is within the range of 0.07-36 mm<2> and opening ratios of these thorough hole are within the range of 10-60% and form of these through holes comprises circular form, semi-circular form, ellipse, sector form, long hole form, star form, cruciate, polygon or the like. This method for producing the setter for baking comprises forming ceramic raw material or the like by slurry slip casting or doctor blade method, forming through holes in the formed product by stamping and baking the formed product.

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), Oxides such as zirconium oxide (ZrO ₂ ), rare earth oxides, glass materials, and composites thereof are used.

[0003] In general, such electronic parts are prepared by blending these materials, shaping them, and placing them on a firing setter.
By firing at 1400 ° C., a ceramic body is formed, and an element is formed by forming an electrode on this body, and finally a component is obtained by assembling.

In recent years, there has been a demand for miniaturization and weight reduction of AV equipment, OA equipment, home electric appliances, etc., in which capacitors and the like are frequently used, and electronic material parts have been miniaturized. An important problem is contamination of the fired material due to contact with the material, or occurrence of defective products due to adhesion between the fired material and the setter.

[0005] In order to solve such a problem, as a method of making the contact between the fired material and the setter a point contact, a ceramic powder or a sintered body which is less likely to react with the fired material is spread as a powder on the setter and fired. The way to be done. However, in this method, since the ceramic powder adheres to the surface of the fired product, the work of removing the adhered powder occurs, or when the firing temperature is increased, the powders aggregate or adhere to each other. It is difficult to use and needs to be treated as industrial waste.

Further, if the calcined material is small, it takes time and effort to collect the calcined material in the collection operation, and the litter is also collected. Therefore, the removal operation occurs. If the calcined material is large, the calcined material comes into contact with the setter. On the surface, there is a trace of bedding powder,
Problems such as the necessity of finishing such as surface polishing have occurred.

[0007] In addition, ceramics slurry which is difficult to react with the fired material is applied to the surface of the firing setter, or a sprayed material of the same material is coated. However, the aspect of preventing contamination is eliminated. However, there are problems such as high coating cost and foreign matter mixing such as cracking and peeling of the coating layer due to the difference in thermal expansion coefficient between the setter material and the coating layer.

On the other hand, as a method of manufacturing an inexpensive setter in which the contact between the fired material and the setter is point contact, a surface of a molded body is blasted using plastic or glass beads, and a roughened surface is sintered. There is a method to make a setter. However, if a material with a high sintering density and low thermal conductivity is used as the setter material, unevenness in the baked product may occur due to the temperature difference on the setter, and the thickness of the setter must be reduced to prevent this. Must. As the thickness of the setter becomes thinner, the formed body is more likely to be broken during blasting, so that a setter thinner than several mm can hardly be manufactured by this method.

There is also a porous setter, but as the thickness becomes thinner, the strength becomes weaker, and there is a problem that foreign matter is mixed in due to chipping of the setter during handling.

[0010]

As a method for producing a setter for firing having a thickness of several mm or less, there are dry press molding in which powder is molded using a mold, cast molding in which slurry is poured into a mold, and slurry injecting. A typical method is to form a molded body by tape molding such as a doctor blade poured onto a sheet and then sinter this to form a setter.

However, if a setter surface is formed with an uneven pattern, it is difficult to form the uneven pattern by mechanical working on a mold such as a gypsum mold in cast molding, or it is difficult to repeatedly form the mold. Releasability is also a problem. It tends to be more difficult as the size of one of the depressions or projections becomes smaller.

[0012] Also in tape molding, as the shape of the concavo-convex pattern becomes more complicated, the problem of releasability arises, and as the thickness of the setter increases, uneven drying and uneven density occur.

In order to solve such a problem, as proposed by the present inventors in Japanese Patent Application No. Hei 8-88477, a resin film or sheet having microspheres adhered to the surface, or depressions or protrusions on the surface. It is inexpensive to use a resin sheet in which the shape of the concavo-convex pattern is formed by machining or the like and press-mold or the like.

However, when the thickness of the resin sheet is reduced, it is difficult to perform machining or heat processing.
The smaller the size of each piece and the more complicated the shape, the narrower the width of the protruding part connected to the ridge line around the depression,
Since the sheet is deformed by pressurization during press molding, the ridgeline of the molded body may be unclear or collapsed, and may be close to surface contact, and the fired product may adhere to the setter.

The present invention has solved these problems.
Since the thickness of the setter is thin, heat is easily transmitted uniformly to the fired material, there is no uneven firing of the fired material due to the temperature difference on the setter, and the sintered body density is high, so there is also mechanical strength, and contact with the fired material Because an independent through hole is formed on the surface,
Good stability of the fired material on the setter, and the fired material and the setter are close to point contact. Because there is no adhesive, even if used repeatedly,
It is an object of the present invention to provide a setter for firing, in which foreign matter is not mixed and a fired product can be easily collected.

[0016]

According to the present invention, the thickness of the setter is in the range of 0.2 mm to 2 mm, the sintered body has a density of at least 95% of the theoretical density, The present invention provides a baking setter, wherein independent through holes are formed in the contact surface. less than,
The requirements for the setter for firing of the present invention to be satisfied,
This will be described in detail.

(A) Thickness of the setter The thickness of the setter must be in the range of 0.2 mm to 2 mm. In the molding method using the slurry, 2 mm
It is difficult to produce thicker sheet-shaped molded products, and this tendency is particularly strong in tape molding such as doctor blades.
When a material having a low thermal conductivity is used, if the thickness of the setter is large, unevenness in the firing of the fired product may occur due to a temperature difference on the setter. Also, even if it is thinner than 0.2 mm,
Although it is possible to manufacture a sheet-like molded body having a uniform thickness, handling of the molded body after punching is difficult, and the molded body is easily broken. This tendency is stronger as the opening ratio of the through holes is higher.

(B) Sintered Body Density The sintered body density of the setter is 95% or more of the theoretical density of the material, and preferably 97% or more. The reason is that if the density of the sintered body is less than 95%, the mechanical strength is inferior, so that chipping may occur at the time of handling, and the chipping may be mixed in when collecting the fired material. . Also, even during firing, the setter may be warped and cannot be reused.

(C) Size of Through-hole Even if through-holes of the same size are formed, depending on the size of the surface where the fired material comes into contact with the setter, there are some that come close to point contact and others that do not. but one area of the independent through holes, is preferably in the range of 0.07mm ² ~36mm ^2, more preferably, 0.2 mm ² to 1
It is preferably within the range of 6 mm ² . In particular, from the stability of the fired material on the setter, one area of the through-hole,
It is preferable to select one that is smaller than half the installation area of the fired product.

If the area of one of the through holes is smaller than 0.07 mm ² , the surface is as good as a flat surface and close to surface contact. Therefore, as the firing temperature increases, the fired material and the setter may adhere to each other. . In addition, when the area of one through hole is larger than 1/2 of the installation area of the fired material on the setter or larger than 36 mm ^2, if the fired material is small, it may fall into the through hole, The baked product may be deformed due to adhesion of the baked product and the setter or sintering at an angle. In particular, when the fired material and the setter adhere to each other and the surface of the fired material becomes dirty, it is necessary to finish the surface of the fired material by surface polishing or the like.

(D) Surface porosity The surface porosity of independent through-holes on the surface is not particularly limited, but is preferably in the range of 10 to 60%.
More preferably, it is good to be in the range of 20 to 50%. The reason is that if the porosity is smaller than 10%, the surface is as good as a flat surface, and the higher the sintering temperature, the more likely the baked product and the setter adhere to each other.
If it exceeds 0%, the thinner the setter becomes,
This is because it is difficult to obtain an independent through hole, it is difficult to perform a punching process, and the strength of the molded body is extremely reduced.

(E) Shape of the through-hole The shape of the independent through-hole is not particularly limited.
Shapes such as circle, semicircle, ellipse, sector, slot, star, cross, polygon, etc. that are easy to process, or those with rounded corners, or a combination of these shapes preferable. In the case of a polygon, the number of corners is not limited, but the number is preferably 10 or less, more preferably 3 to 6 in terms of ease of machining.

(F) Material of the Setter The material for the setter is not particularly limited as long as it is a material capable of forming a through hole on the surface, but alumina, silica, mullite, magnesia, zirconia, cordierite, silicon nitride, It is preferable to use ceramics such as silicon carbide or a composite material containing these as a main component.

For example, in the case of zirconia, since the bulk density is higher and the thermal conductivity is lower than other materials, depending on the sintering conditions, a temperature difference may occur on the setter, and the sinter may have uneven sintering characteristics. It had occurred. For this reason, measures to reduce productivity, such as slowing down the heating rate, were required.However, this phenomenon was considerably mitigated by reducing the thickness of the setter and forming independent through holes on the surface. You.

(G) Method of forming through-holes There is no particular limitation on the method of obtaining a molded article having independent through-holes formed on the surface. For example, as a method of obtaining a sheet-like molded body, there is a method of casting such as casting a slurry into a mold or a method of tape forming such as a doctor blade of flowing a slurry onto a sheet. The latter is preferred. The obtained sheet-like molded body is punched using a punching die, and holes are formed at regular intervals in the molded body, whereby a molded body having independent through holes formed on the surface is obtained. In particular, in order to improve the releasability of the molded body and the punching die, it is preferable that the working surface of the punching die is tapered.

(H) Powder Characteristics As a powder characteristic for obtaining a molded body having independent through holes by a molding method using a slurry, a powder having good dispersibility and good fluidity is preferable. Also, 95% of the theoretical density
In order to obtain a setter having a sintered body density corresponding to the above, it is necessary to use a powder having a good sintering property. Therefore, it is preferable to use a powder having an average particle diameter of several μm or less.

However, as the thickness of the setter becomes thinner,
Because it is easy to break at the time of punching, the appropriate addition amount varies depending on the type and particle size of the raw material, or the manufacturing method, but as a binder to maintain the strength of the molded body, in the case of cast molding,
It is preferable to add about 0.6 to 2% of a binder or PVA or the like mainly composed of an acrylic resin having excellent thermal decomposability, mainly a deflocculant. In the case of tape molding such as a doctor blade, the acrylic resin is used. It is preferable to add about 7 to 15% of a binder or PVB as a main component.

Hereinafter, a method for producing a zirconia setter which is an example of the firing setter of the present invention will be described.

The zirconia powder used for the zirconia setter can be produced by an electrofusion method, a hydrolysis method, a neutralization coprecipitation method,
There are a hydrolysis-neutralization method, a hydrothermal oxidation method, a thermal decomposition method, an alkoxide method, etc., but there is no particular limitation. From the type,
As the particle size, it is preferable to use a powder having an average particle size of several μm or less.

Further, MgO, CaO,
Rare earth oxides such as Y ₂ O ₃ and CeO ₂ are often used. However, when used as a setter, they need only be thermally and mechanically stable, and there is no particular need to limit the stabilizer. For example, in the case of Y ₂ O ₃ , the molar ratio of Y ₂ O ₃ / ZrO ₂ is preferably 1.5 / 98.5 to 6.0 / 94.0. If the ratio is less than 1.5 / 98.5, the amount of monoclinic zirconia increases, and the setter becomes weaker in thermal shock resistance due to the transition. If the ratio exceeds 6.0 / 94.0, the smaller the thickness of the setter becomes, the more mechanically the setter becomes. The strength is weak and cannot be reused.

In addition to the stabilizer and the unavoidable components,
To improve heat resistance and mechanical strength, Al ₂ O ₃ , Ti
Oxides such as O ₂ and SiO ₂ or their compounds may coexist. The content does not need to be limited as long as it does not react with or adhere to the fired product at the time of firing. If the content is more than 30% by mass, the original properties of zirconia such as toughness will be reduced.

For example, an average particle diameter of 1 μm containing no stabilizer
m, zirconia powder of not more than 3 m, and 3% by mole of yttria powder as a stabilizer added to the zirconia powder.
0 part, water 50 parts, dispersant 2 parts, binder 0.
3 parts and 0.2 part of an antifoaming agent were added to a ball mill for 24 hours.
After mixing for a time, the resulting slurry is defoamed under reduced pressure, and cast to a size of 150 mm × 150 mm × 2 mm in thickness. Further, after demolding, the obtained molded body has dimensions of 100 mm × 100 mm, the shape of the through hole is square, the porosity of the surface is 59.2%, and the area of one through hole in the size after firing. Is 1 mm ² , and the pitch between the through holes is 1.3 mm
To obtain a molded body having independent through holes formed in the surface. By firing the obtained molded body at 1500 ° C. in a firing furnace in the atmosphere, a firing setter having a thickness of about 1.6 mm is obtained.

[0033]

As described above, in the firing setter of the present invention, since the thickness of the setter is thin, heat is easily transmitted uniformly to the fired material, and there is no uneven firing of the fired material due to a temperature difference on the setter. Since the sintered body density is high, there is also mechanical strength, and since an independent through hole is formed on the setter surface, the stability of the fired material on the setter is good, and the fired material and the setter are close to point contact, Even if the firing temperature increases,
Since the baked product and the setter are not easily adhered to each other and there is no adhesive such as bedding powder or a sintered body on the setter surface, even if used repeatedly, there is no foreign matter contamination and the baked product can be easily collected.

When this setter is used, even if a fired material having a large amount of glass components is fired at a temperature close to the melting temperature of the glass, the fired material and the setter hardly adhere to each other, and the fired material can be easily collected. In addition, since no litter is used, there is no problem of industrial waste.

The use of the sintering setter makes it possible to meet strict requirements for manufacturing conditions, such as prevention of adhesion to the setter due to downsizing of the baked product or prevention of adhesion due to higher sintering temperature.

[0036]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

Example 1 Commercially available zirconia powder (TZ-3YS) manufactured by Tosoh Corporation
100 parts by weight, 25 parts by weight of water, Toa Gosei Co., Ltd.
After adding 2.5 parts by weight of a dispersant (Aron A-6114) manufactured by Daiichi Kogyo Seiyaku Co., Ltd. for 4 hours, 5 parts by weight of a plasticizer (Ceramo P-17) manufactured by Daiichi Kogyo Seiyaku Co., Ltd. Binder (Ceramo TB-13) 35 manufactured by Ichi Kogyo Seiyaku Co., Ltd.
Parts by weight, an antifoaming agent (Surfynol 4) manufactured by Nissin Chemical Co., Ltd.
40) The mixture to which 0.2 parts by weight was added was mixed with a ball mill for 24 hours to obtain a slurry. To the obtained slurry, 0.1 part by weight of Surfynol 440 was further added, followed by defoaming under reduced pressure, and a doctor blade device (manufactured by Tsukawa Seiki Seisaku-sho, Ltd.) equipped with a polyester film having a thickness of 75 μm and a width of 200 mm: DP-150).
It is molded to a thickness of 1.4 mm, a width of 150 mm, and a length of 800 mm at 2 m / min. Leave at room temperature for 24 hours
Air drying for 12 hours, and then oven drying at 60 ° C for 12 hours.
After drying for 12 hours at 100 ° C., the film is separated from the film to obtain a sheet-like molded body. The size after firing is 100 mm x 100 mm, and the shape of the through hole is 1 m on each side
m square, surface porosity 59.2%, area of one through hole is 1 mm ² , and pitch between through holes is 1.3 mm (parallel type). To obtain a molded body in which independent through holes were formed. The obtained compact was set on an alumina setter for firing, and a warp prevention setter was placed on the upper surface thereof.
It is fired at 0 ° C. for 2 hours and has a sintered body density of 6.00.
A zirconia setter with a thickness of about 1 mm was obtained in which independent through holes were formed on the contact surface with the fired product of g / cm ³ (corresponding to 98.3% of the theoretical density).

On this zirconia-based setter, 10 compacts each made of barium titanate and having a width of 3 mm, a length of 5 mm, and a thickness of 2 mm (installation area: 15 mm ² ) were placed, and placed in an air furnace at 1330 ° C. After firing for 2 hours, there was no reaction or adhesion between the setter and the fired product.

Example 2 Commercially available zirconia powder (TZ-3Y) 1 manufactured by Tosoh Corporation
45 parts by weight of water, 1 part by weight of a dispersant (Cerna D-305: solid content 40%) manufactured by Chukyo Yushi Co., Ltd., and 0.1 part by weight of PVA (PVA-205) manufactured by Kuraray Co., Ltd. 3
The resulting mixture was mixed for 24 hours with a ball mill to obtain a casting slurry. To the obtained slurry, 0.2 parts by weight of an antifoaming agent (Surfinol 440) manufactured by Nissin Chemical Co., Ltd. was added, degassed under reduced pressure, and the slurry was poured into a gypsum mold having a size of 150 mm × 150 mm. After the thickness was reduced to 2.5 mm, the sludge was discharged. After demolding, the obtained molded body was allowed to stand at room temperature for 24 hours.
For 12 hours, and punched out with the same punching die as in Example 1 to obtain a molded body having independent through holes formed on the surface.
The obtained molded body was set on an alumina setter for firing, a warp prevention setter was placed on the upper surface thereof, and fired in an electric furnace under the same conditions as in Example 1 under an air atmosphere. Is 100 mm × 100 mm, the shape of the through-hole is 1 mm on a side, and the surface porosity is 59.2%.
The area of one through hole is 1 mm ² , the pitch between the through holes is 1.3 mm (parallel type), and the sintered body density is 5.95 g / cm ³
A zirconia setter having a thickness of about 2 mm in which independent through holes were formed on the contact surface with the fired product (equivalent to 97.5% of the theoretical density) was obtained.

On this zirconia-based setter, 10 compacts each made of barium titanate and having a width of 3 mm, a length of 5 mm, and a thickness of 2 mm (installation area: 15 mm ² ) were placed, and were placed in an air furnace at 1330 ° C. After firing for 2 hours, there was no reaction or adhesion between the setter and the fired product.

Comparative Example 1 The size of the sheet-shaped compact obtained in Example 1 after firing was 100 mm × 100 mm, and the shape of the through-hole was 2 mm.
mm, the surface porosity is 7.5%, the area of one through hole is 3.14 mm ² , and the pitch between the through holes is 7 mm (60 mm).
(Staggered type) to obtain a formed body having independent through holes formed in the surface. The obtained molded body is set on an alumina setter for firing, a warp prevention setter is placed on the upper surface thereof, and an electric furnace is used under an air atmosphere.
Baking under the condition of 1500 ° C. and holding for 2 hours, the thickness at which an independent through-hole is formed on the contact surface with a baked product having a sintered body density of 6.00 g / cm ³ (equivalent to 98.3% of theoretical density) About 1
mm zirconia setter was obtained.

On the zirconia-based setter, 10 compacts each made of barium titanate and having a width of 3 mm, a length of 5 mm, and a thickness of 2 mm (installation area: 15 mm ² ) were placed. Although firing was performed under the condition of holding for 2 hours, the contact between the setter and the fired product was a surface contact, and a part of the fired product was adhered and deformed.

Comparative Example 2 The size of the sheet-like molded body obtained in Example 1 after firing was 100 mm × 100 mm, and the shape of the through-hole was 2 sides.
mm square, the surface porosity was 90.7%, the area of one through hole was 4 mm ² , and the pitch between the through holes was 2.1 mm (parallel type). As a result, the independent through-holes collapsed and through-holes with a wide pitch were formed, resulting in a molded article having low strength.

[Brief description of the drawings]

FIG. 1 is a top view of a circular parallel type through-hole setter and a formula for calculating the opening ratio thereof.

FIG. 2 is a top view of a circular 60 ° staggered through-hole setter and a formula for calculating the opening ratio thereof.

FIG. 3 is a top view of a square staggered through-hole setter and a formula for obtaining the opening ratio.

FIG. 4 is a top view of an elongated parallel-type through-hole setter and a formula for calculating the opening ratio thereof.

[Explanation of symbols]

 D: Hole diameter (mm) of the through hole. P: pitch (mm) between through holes. W: The width (mm) of the through hole. EC: lateral pitch (mm) between through holes. SC: lateral pitch (mm) between through holes.

FIG. 5 is an example of a top view of another through hole setter shape.

FIG. 6 is an example of a top view of another through hole setter shape.

FIG. 7 is an example of a top view of another through hole setter shape.

FIG. 8 is an example of a top view of another through hole setter shape.

FIG. 9 is a top view example of another through hole setter shape.

FIG. 10 is an example of a top view of another through hole setter shape.

FIG. 11 is a top view example of another through hole setter shape.

Claims (6)

[Claims] The thickness of the setter is from 0.2 mm to 2 mm.
Characterized by having a sintered body density equal to or more than 95% of the theoretical density, and having an independent through hole formed in a contact surface with a fired material. 2. The area of one of the through holes according to claim 1 is:
A firing setter characterized by being in the range of 0.07 mm ² to 36 mm ² . 3. The firing setter according to claim 1, wherein the porosity of the independent through holes according to claim 1 is in the range of 10% to 60%. 4. The through hole according to any one of claims 1 to 3, wherein the shape of the through hole is a circle, a semicircle, an ellipse, a sector, a slot, a star, a cross, a polygon, or the like. Or a baking setter characterized by rounded corners of these shapes or a combination of these shapes. 5. The setter material according to any one of claims 1 to 4, wherein the material of the setter is ceramics such as alumina, silica, magnesia, mullite, zirconia, cordierite, silicon nitride, silicon carbide or the like. A firing setter characterized by comprising a composite material as a component. 6. The setter according to any one of claims 1 to 5, which is formed by a slurry casting method or a doctor blade method, and then a through hole is formed in the formed body by punching. A method for producing a firing setter, characterized by firing.