KR19990072433A - Filtration forming mold and method for producing ceramics sintered body using the same - Google Patents

Abstract

SUMMARY OF THE INVENTION An object of the present invention is to provide a molded article having low incorporation of impurities, no internal defects, no density or compositional irregularities, and a molded article having a thickness difference in the manufacture of a ceramic sintered body and the obtained molded article. The present invention provides a method for producing a high-purity ITO sintered body of a large size free from defects such as cracks and cracks after firing by increasing the anti-freeze strength.

The present invention relates to a filter-type mold comprising a water-insoluble material for obtaining a ceramic molded body by draining water from a ceramic raw material slurry under reduced pressure, wherein the lower mold for molding having one or more drain holes, the water permeability placed on the lower mold for molding It consists of a molding die frame sandwiched from the upper surface side through the filter and the sealing material for sealing the filter, and the lower mold, the mold frame, the sealing material and the filter for assembly are assembled so as to disassemble, respectively, the filter Provided is a filtration shaping mold which drains water in a slurry under reduced pressure only on the surface side.

In addition, the present invention is to prepare a slurry consisting of indium oxide powder, tin oxide powder, ion-exchanged water and an organic additive, injecting the slurry into the above-mentioned filtration type mold, and draining the water in the slurry under reduced pressure only on the filter surface side, There is provided a method for producing an ITO sintered body having a thickness difference in which the obtained and the obtained ITO molded body is calcined after dry degreasing.

Description

Filtration type mold and manufacturing method of ceramic sintered body using the mold {FILTRATION FORMING MOLD AND METHOD FOR PRODUCING CERAMICS SINTERED BODY USING THE SAME}

The present invention relates to a method for producing a ceramic sintered body having a high thickness difference, which is suitable for use as a high-purity sputtering target and an ITO sputtering target used for the formation of a transparent conductive film by a filtration molding type and a sputtering method used for molding a ceramic molded body. It is about.

ITO thin films made of indium oxide and tin oxide are widely used as transparent conductive films such as liquid crystal displays. As a formation method of this IT0 thin film, the sputtering film-forming method using an ITO sintered compact as a target material is common.

In recent years, with the expansion of the liquid crystal display size, the enlargement of the ITO target material is progressing. As a manufacturing method of an ITO sintered compact, there exists a method of baking by the metal mold | die press method and the obtained ITO molded object. However, this mold press method has a problem that the mold and the press equipment cost increase with the increase in the size of the molded body. Moreover, in the dry press molding method using a metal mold | die, it is hard to be uniform in the molded object with a thickness difference, and it becomes easy to bend and crack in a molded object.

On the other hand, conventionally, there is a molding method for injecting two sheets of ceramic using a gypsum mold or the like as a manufacturing method of a molded article having a low equipment cost. This method is a method of injecting a slurry under pressure into an absorbent porous hermetic mold such as gypsum and absorbing it from the front or two sides of the mold (JP-A 6-659). However, in this method, since the central part of the molded body is hardened to have a thickness last, defects such as density unevenness and compositional unevenness tend to occur. Since it is low, defects, such as a crack, arise easily by baking, and a high density sintered compact is not necessarily obtained. In addition, since the gypsum used for double injection molding is water soluble, the incorporation of calcium into the molded body cannot be prevented. The ceramic sintered body, which is a functional material such as a sputtering target, is preferably of high purity, but incorporation of calcium in this adversely affects the conductivity, transparency, and etching property of the thin film formed by sputtering.

In addition, there is a method of compacting by cold hydrostatic press after double injection molding to improve the density (for example, Japanese Patent Application Laid-Open No. 8-11711). However, since this method requires a cold hydrostatic press, the equipment cost increases.

SUMMARY OF THE INVENTION An object of the present invention is to provide an inexpensive molding for producing a molded article having a small amount of impurities, no internal defects, no density or compositional irregularities, and a thickness difference in the production of a ceramic sintered body.

Another object of the present invention is to provide a method of increasing the anti-glaze strength of the obtained molded product and producing a high-purity ITO sintered body of a large size without defects such as cracks and cracking after firing.

Another object of the present invention is to provide a method for producing a high purity IT0 sintered body obtained by molding a slurry containing indium oxide and tin oxide and an ITO sintered body having a high thickness difference as a sputtering target. .

Means to solve the problem

MEANS TO SOLVE THE PROBLEM The present inventors used the filtration shaping | molding die which consists of a water-insoluble material as a shaping | molding die which replaces the conventional plaster injection mold | type, and it produces | generates in one direction of thickness, and there exists no density unevenness or a composition nonuniformity, It was found that a high-purity ceramic sintered body without mixing of was obtained.

In addition, the inventors of the present invention can use a relatively small strength as the material because the filter-type mold has a low load on the lower mold, so that the mold can be provided at a low cost even if the molding size is increased. It was discovered that a molded article having a thickness difference can be obtained by processing the lower mold for molding into an uneven shape.

The present inventors also found that by limiting the specific surface area of indium oxide and tin oxide to a specific range, the strength of the molded article obtained by the filtration molding increases, and thus a high-density ITO sintered body free from defects such as cracks and cracks suitable for the enlargement of the molding size is obtained. It was found to be obtained.

This invention is characterized by the following matters.

(1) A filter-forming mold comprising a non-aqueous material for obtaining a ceramic molded body by draining water from a ceramic raw material slurry under reduced pressure, wherein the lower mold for molding having at least one water drain hole and the water permeability placed on the lower mold for molding It consists of a molding die frame sandwiched from the upper surface side through the filter and the sealing material for sealing the filter, and the lower mold, the mold frame, the sealing material and the filter for assembly are assembled so as to disassemble, respectively, the filter A filtration molding type, wherein the water in the slurry is drained under reduced pressure only at the surface side.

(2) The filter type shaping | molding die as described in said (1) characterized by the filter surface side of the lower mold for shaping | molding.

(3) A slurry composed of ceramic raw material powder, ion-exchanged water and organic additive is prepared, and the slurry is poured into the filtration type mold as described in the above (1), and the water in the slurry is drained under reduced pressure only on the filter surface side thereof. A method for producing a high purity ceramic sintered body, wherein a molded product is produced and the obtained ceramic molded product is baked after dry degreasing.

(4) A slurry composed of a ceramic raw material powder, ion exchanged water and an organic additive is prepared, and the slurry is poured into a filtration type mold as described in the above (2), and the water in the slurry is drained under reduced pressure only on the filter surface side thereof. A method for producing a ceramic sintered body having a thickness difference, wherein the molded body is produced, and the obtained ceramic molded body is fired after dry degreasing.

(5) A slurry composed of indium oxide powder, tin oxide powder, ion-exchanged water, and an organic additive is prepared, and the slurry is injected into the filtration type mold as described in (1) above, and water in the slurry is supplied only at the filter face side. A method for producing a high purity ITO sintered compact, wherein the molded article is produced by draining under reduced pressure, and the obtained ITO molded article is baked after dry degreasing.

(6) A slurry composed of indium oxide powder, tin oxide powder, ion-exchanged water, and an organic additive is prepared, and the slurry is injected into the filtration type mold as described in (2) above, and water in the slurry is supplied only at the filter face side. A method for producing an IT0 sintered body having a thickness difference, wherein the molded product is produced by draining under reduced pressure and baking the obtained ITO molded product after dry degreasing.

(7) The method for producing the IT0 sintered body according to the above (5) or (6), wherein the specific surface area of the indium oxide powder is 4.6 m 2 / g or more and 14.6 m 2 / g or less, and the tin surface of the tin oxide powder is 7.2 m 2 / g or less. .

(8) An ITO sintered body having a relative density of 97.5% (density 6.97 g / cm 3) or more obtained by drying the IT0 molded body produced by the method described in the above (7), and then firing in an oxygen atmosphere.

BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing which shows the structure of the filtration shaping | molding die (flat plate shaping | molding die) which concerns on this invention.

It is explanatory drawing which shows the structure of the filtration type shaping | molding die (uneven | corrugated shape shaping | molding die) which concerns on this invention.

It is explanatory drawing which shows the manufacturing process of the ceramic sintered compact by the filtration molding method which concerns on this invention.

It is explanatory drawing which shows the manufacturing process of the ITO sintered compact by the filtration molding method which concerns on this invention.

In the filtration type mold of the present invention, the ceramic raw material slurry 1 is injected into the mold frame 2 from the top as shown in FIGS. 1 (flat plate mold) and 2 (uneven shape mold), and The molded object is obtained by depressurizing drainage in one or more drain holes 6 arranged.

The filtration type mold is a filter having water permeability through which ceramic powder in the slurry 1 does not penetrate into the lower mold 3 for molding made of aluminum or resin (polypropylene, nylon, etc.) having the water drain hole 6. (4) An aluminum molding die frame (2) is sandwiched through the lower die (3) and the sealant (5) for forming the mold (for example, Gore-Tex wet filter cross, manufactured by Japan Gore-Tex Co., Ltd.). It consists of a structure.

In the molding die of the present invention, since the pressure applied at the time of reduced pressure drainage is applied only between the filter and the lower mold for molding, a material having a relatively small strength can be used as the lower mold for molding.

Next, the manufacturing method of the ceramic and IT0 sintered compact using the filter shaping | molding die of this invention is demonstrated. The manufacturing process of a ceramic sintered compact is shown in FIG. 3, and the manufacturing process of an ITO sintered compact is shown in FIG.

(a) adjustment of raw material powder

Slurrying can be facilitated by calcining or pulverizing a ceramic raw material powder, and adjusting a primary particle diameter or a specific surface area.

In the case of the ITO sintered compact, commercially available products may be used for the indium oxide powder and the tin oxide powder, and it is preferable that the indium oxide powder is grain grown in advance by treatment such as calcination. If the primary particle size of the indium oxide powder becomes inappropriate, the thickness of the indium oxide powder decreases, degreasing due to density nonuniformity, cracks, cracks, and warpage in sintering become large. Therefore, the indium oxide powder is preferably in the range of 0.1 to 0.5 µm.

Commercially available indium oxide powder and tin oxide powder tend to aggregate into fine particles, so that the specific surface area can be changed by calcination. The specific surface area of the indium oxide powder is 4.6-14.6 m <2> / g. If the specific surface area exceeds 14.6 m 2 / g, cracks are likely to occur in the sintered body. On the other hand, if the specific surface area is less than 4.6 m 2 / g, the anti-glaze strength after degreasing is small, and cracks and cracks are likely to occur in the molded body and the sintered body.

(b) preparation of slurry

The slurry is adjusted by ball mill mixing the ceramic raw material powder alone or in various kinds, by adding ion-exchanged water and an organic additive (dispersant, binder, antifoaming agent). In the case of an ITO sintered compact, indium oxide powder and tin oxide powder which are raw materials are mixed and pulverized by a wet ball mill previously. The composition of tin oxide is preferably 5 to 10% by weight. At this time, if 1 to 5% by weight of ion-exchanged water is added, the effect of reducing the adhesion of the raw material powder to the port wall and sufficiently mixing can be expected. It is preferable to use a resin pot as the pot of the ball mill. In addition, the material of the ball is preferably zirconia having a high specific gravity and excellent wear resistance. Dry ball mills disintegrate the aggregated particles and increase the bulk density of the powder.

Next, 10-25% by weight of ion-exchanged water and an organic additive (dispersant) are added to the ball mill pot and mixed in a resin pot to disperse the raw material powder. As the dispersant, a polycarboxylic acid dispersant may be used, and the amount of addition is preferably 0.2 to 1.0% by weight.

In addition, an organic additive (binder) is added and mixed to obtain a slurry. As the binder, a wax-based binder can be used, and the amount of addition is preferably 0.3 to 1.0% by weight. As a slurry viscosity, it is preferable to prepare the slurry of 100cp or less. If the slurry viscosity is high, deaeration becomes difficult, or the slurry recovery rate decreases due to adhesion to a container or a ball.

Finally, an organic additive (antifoaming agent) is added to the slurry and degassed under reduced pressure. As the antifoaming agent, an amide antifoaming agent can be used, and the amount of addition is preferably 0.01 to 0.5% by weight.

(c) Preparation of molded article by filtration type

The degassed slurry is poured into a mold, and the lower mold surface side of the filter is depressurized, and the water in the slurry is molded by draining the pressure at the filter surface side under reduced pressure. It is preferable that the decompression is larger than -700 mmHg. A vacuum pump etc. can be used for pressure reduction.

The reduced-pressure drainage time may be from about 30 minutes after the end of the hardening to cause the thickness of the molded body. If the decompression drainage time is short, the releasability of the molded body from the mold frame for molding is poor and cracks may occur. If the decompression drainage time is too long, the molded body is released from the mold frame for decompression drainage, and air is sucked in the gap, and only the release part of the molded body is rapidly dried, causing cracks.

(d) drying and degreasing of the molded body

It is preferable to naturally dry the molded object obtained in this way. The molded article contains about 10% by weight of water at the time of mold release, and if the molded article is rapidly dried by using a dryer or the like, the molded article may be warped and cracked due to dry unevenness.

Moreover, the dry molded object is degreased. If the molded product is not degreased, bending, cracks and cracks are likely to occur in the molded product during firing. Degreasing is preferably carried out using a hot air circulation degreasing furnace at 400 to 600 ° C. to remove residual moisture and binder.

(e) Firing of the molded body

The high purity ceramic sintered compact is obtained by baking a molded object. In the case of the ITO sintered compact, the firing temperature is preferably 1400 to 1600 ° C. The minor component atmosphere can use atmospheric air and oxygen, but it is preferable to use an oxygen atmosphere in order to obtain a high density sintered compact.

The advantage compared with the conventional mold regarding the shaping | molding die of this invention is shown in Table 1. Compared with conventional gypsum molds and press molds, the molding die of the present invention has no density nonuniformity or composition nonuniformity, no impurities are mixed, and the cost for increasing the size is reduced. In addition, there are similar advantages in molding a molded article having a thickness difference.

assignment Invention type Conventional example Plaster Press mold Density non-uniformity ○ △ △ Composition heterogeneity ○ △ ○ Impurity incorporation ○ × ○ Larger Cost ○ △ × Thickness difference ○ ○ △

Example

Below, this invention is further demonstrated by an Example and a comparative example.

Example 1

15000 g of commercially available low soda alumina powder, 3450 g of ion-exchanged water, 150 g of polycarboxylic acid-based dispersant, 150 g of wax-based binder, and a resin ball containing an iron core were placed in a resin pot and ball milled for 40 hours. The slurry had a concentration of 83%, an average particle diameter of 0.76 µm, and a viscosity of 105 cps.

After depressurizing and degassing, the slurry was injected into a molding die of the present invention in which a molding die frame having a molding size of 1050 mm × 1100 mm × 10 mm was made of aluminum and the lower mold for molding was made of resin, and drained under reduced pressure on the filter face side to obtain a molded body.

The filter used Gore-Tex R wet filter cross (made by Japan Gore-Tex). The filter has a structure in which a porous resin film is attached only to one surface side on a woven fabric or felt, and the back side of the resin has a water passage space formed of a woven fabric or felt, and water moves freely between the porous resin film and the lower mold. A passage is formed.

The molded body was dehydrated at 450 ° C. after natural drying. There was no warping or cracking due to density nonuniformity in the molded body after degreasing, the dimension was 1049 mm x 1099 mm x 10.2 mm, and the density was 55% (2.19 g / cm 3).

The definition of slurry concentration is as follows.

Slurry Concentration (%) = Solute Weight / (Solute Weight + Solvent Weight) x 100

Example 2

250 g of commercially available tin oxide powder, 1.25 g of ion-exchanged water, and zirconia ball were placed in a resin pot and ball milled for 20 hours. Next, 233 g of ion-exchanged water and 2 g of a polycarboxylic acid dispersant were added and ball milled for 1 hour. After 1 hour, 2.5 g of a wax-based binder was added and ball milled for 19 hours. The slurry had a concentration of 83%, an average particle diameter of 1.1 mu m, and a viscosity of 71 cps.

After degassing under reduced pressure, the slurry was poured into the molding die of the present invention having the same shape and material as in Example 1 except that the molding size was 76 mm ø, and drained under reduced pressure at -760 mmHg to obtain a molded product. After naturally drying the molded body, degreasing treatment was performed at 600 ° C for 3 hours. Thereafter, the mixture was calcined at 1500 ° C. for 8 hours in an oxygen atmosphere to obtain a tin oxide sintered body. The sintered compact did not generate warpage or cracks due to density irregularities, and the density was 66.5% (4.6 g / cm 3). Moreover, the high purity sintered compact in which calcium was not mixed as an impurity was obtained.

Example 3

7200 g of indium oxide powder, 800 g of tin oxide powder, 240 g of ion-exchanged water, and a zirconia ball having a diameter of 5 mm were placed in a resin pot and ball milled for 20 hours. Next, 1440 g of ion-exchanged water and 56 g of a polycarboxylic acid dispersant were added and ball milled for 1 hour. After 1 hour, 80 g of a wax-based binder was added and ball milled for 19 hours.

Next, 1.6 g of an amide defoaming agent was added to the slurry to perform depressurization. The slurry had a concentration of 83%, an average particle diameter of 0.5 µm and a viscosity of 33 cps. This slurry was poured into the same structural mold as in Example 1 except that the molding mold was 300 mm × 700 mm and the lower mold for molding was made of aluminum, and drained under reduced pressure at -760 mmHg to obtain a compact.

The molded product was naturally dried and degreasing treatment was performed at 600 ° C for 3 hours. Thereafter, the mixture was calcined at 1550 ° C. for 8 hours in an oxygen atmosphere. The ITO sintered compact did not generate warpage or cracks due to density nonuniformity. In addition, a high-purity ITO sintered body having no segregation of tin oxide and free of calcium was obtained. The dimension of the ITO sintered compact was 247 mm x 578 mm x 7.3 mm, and the density was 98.1% (7.01 g / cm <3>).

Example 4

18000 g of indium oxide powder, 2000 g of tin oxide powder, 600 g of ion-exchanged water, and a zirconia ball having a diameter of 5 mm were placed in a resin pot and ball milled for 20 hours. Next, 3592 g of ion-exchanged water and 160 g of a polycarboxylic acid dispersant were added and ball milled for 1 hour. After 1 hour, 200 g of a wax-based binder was added and ball milled for 19 hours.

4 g of an amide defoaming agent was added to the slurry to perform depressurization. The slurry had a concentration of 83%, an average particle diameter of 0.5 µm and a viscosity of 40 cps. The slurry was poured into the same structural mold as in Example 1 except that the lower mold for molding size 375 mm x 1270 mm was made of aluminum, and the product was drained under reduced pressure at -760 mmHg under reduced pressure.

The molded product was naturally dried and degreasing treatment was performed at 600 ° C for 3 hours. Thereafter, the mixture was calcined at 1550 ° C. for 8 hours in an oxygen atmosphere. The ITO sintered compact did not generate warpage or crack due to density nonuniformity. In addition, a high-purity ITO sintered body having no segregation of tin oxide and free of calcium was obtained. The dimension of the ITO sintered compact was 308 mm x 1046 mm x 7.9 mm, and the density was 98.8% (7.06 g / cm <3>).

Example 5

900 g of indium oxide powder, 100 g of tin oxide powder, 30 g of ion-exchanged water, and a zirconia ball having a diameter of 5 mm were placed in a resin pot and ball milled for 20 hours. Next, 178 g of ion-exchanged water and 7.9 g of a polycarboxylic acid dispersant were added and ball milled for 1 hour. After 1 hour, 9.9 g of a wax binder was added and ball milling was carried out for 19 hours.

0.2 g of an amide defoaming agent was added to the slurry, and depressurization was carried out. The slurry had a concentration of 83%, an average particle diameter of 0.46 µm and a viscosity of 15 cps. This slurry was poured into the same structural mold as in Example 1 except that the lower mold for molding was made of aluminum at a molding size of 190 mm, and the product was drained under reduced pressure at -760 mmHg under reduced pressure.

After naturally drying the molded body, degreasing treatment was performed at 600 ° C for 3 hours. Thereafter, the mixture was calcined at 1550 ° C. for 8 hours in an oxygen atmosphere. The ITO sintered compact did not generate warpage or crack due to density nonuniformity. In addition, a high-purity ITO sintered body having no segregation of tin oxide and free of calcium was obtained. The dimensions of the ITO sintered compact were 157 mm x 7.9 mm, and the density was 99.5% (7.11 g / cm 3).

Example 6

720 g of indium oxide powder, 80 g of tin oxide powder, 24 g of ion-exchanged water, and a zirconia ball having a diameter of 10 mm were placed in a resin pot and ball milled for 20 hours. Next, 128 g of ion-exchanged water and 6.4 g of a polycarboxylic acid dispersant were added and ball milled for 1 hour. After 1 hour, 8.0 g of a wax binder was added and ball milling was carried out for 19 hours.

0.4 g of an amide defoaming agent was added to the slurry to perform degassing under reduced pressure. The slurry had a concentration of 83%, an average particle diameter of 0.53 µm and a viscosity of 28 cps. The slurry was poured into a mold having the same structure as in Example 1 except that the slurry was formed with a molding size of 190 mm ø with a concave depth of 5 mm in width and 30 mm in depth on the filter face side, and drained under reduced pressure at -760 mmHg to obtain a molded product.

After naturally drying the molded body, degreasing treatment was performed at 600 ° C for 3 hours. Thereafter, the mixture was calcined at 1550 ° C. for 8 hours in an oxygen atmosphere. The ITO sintered compact did not generate warpage or crack due to density nonuniformity. The dimension of the ITO sintered compact was 156.6 mm x 3.52 (thin part) "6.56 mm (thick part)", and the density was 99.3% (7.10 g / cm <3>).

Comparative Example 1

6930 g of indium oxide powder, 770 g of tin oxide powder, and zirconia ball were placed in a resin pot and ball milled for 20 hours. 6.0 weight% of 4 weight% polyvinyl alcohol aqueous solution of density | concentration was added to the raw material powder taken out from the pot, and it stirred and mixed. Next, this raw material powder was pulverized after pressing at a pressure of 500 kgf / cm 2 and was sized to 60 mesh or less. This sized powder was put into the metal mold | die of shaping | molding size 200x980, and it shape | molded at the pressure of 1000 kgf / cm <2>.

The crack which generate | occur | produced by density nonuniformity generate | occur | produced in the molded object. The size of the molded body was 201.0 mm x 982.0 x 9.26 mm, and the density was 61.0% (4.36 g / cm 3).

Comparative Example 2

The slurry of Example 5 was inject | poured into the plaster mold of molding size 190mm * 8.5mm by the pressure of 1.0 kg / cm <2>, and the molded object was obtained. The molded body was naturally dried and then degreased at 600 ° C for 3 hours.

Thereafter, the mixture was calcined at 1550 ° C. for 8 hours in an oxygen atmosphere to obtain an ITO sintered body. At this time, the density of the ITO sintered compact was 97.2% (6.95 g / cm <3>). In the center of 1TO sintered body, stem-shaped defects were observed, and segregation of tin oxide was observed by EPMA analysis. In addition, 35 ppm of calcium was detected as an impurity.

As described above, when Examples 1 to 6 using the filtration type mold of the present invention and Comparative Examples 1 and 2 using a gypsum mold or a press mold are compared, the examples of the present invention have a thickness and harden only in one direction. A defect such as density unevenness or composition unevenness does not occur inside the molded body, and a high-purity molded article having a thickness difference without impurity mixing is obtained.

Example 7

900 g of indium oxide powder having a specific surface area of 8.07 m 2 / g, 100 g of tin oxide powder having a specific surface area of 2.2 m 2 / g, 30 g of ion-exchanged water, and a zirconia ball having a diameter of 5 mm were placed in a resin pot and ball milled for 20 hours. Next, 178.3 g of ion-exchanged water and 7.9 g of a polycarboxylic acid dispersant were added and ball milled for 1 hour. After 1 hour, 9.9 g of the wax-based binder was added, followed by ball mill mixing for 19 hours.

Next, 0.2 g of an amide defoaming agent was added to the slurry, and degassing was carried out. The concentration of this slurry was 83%.

This slurry was poured into a mold for molding of 190 mm ø of the structure shown in FIG. 2 and drained at a reduced pressure of -760 mmHg to obtain a molded product. The molded body was degreased at 600 ° C for 9 hours after drying at 25 ° C. The anti-stone strength after degreasing was 0.94 kgf / mm 2. The degreased molded body was calcined at 1550 ° C. for 8 hours in an oxygen atmosphere to obtain an ITO sintered body. The dimension of the ITO sintered compact was 157.3 mm * 6.1 mm, and the density was 99.4% (7.11 g / cm <3>).

Example 8

7200 g of indium oxide powder having a specific surface area of 8.52 m 2 / g, 800 g of tin oxide powder having a specific surface area of 2.95 m 2 / g, and 240 g of ion-exchanged water were put together with a zirconia ball having a diameter of 5 mm into a resin pot for ball mill mixing for 20 hours. Next, 1440 g of ion-exchanged water and 64 g of a polycarboxylic acid dispersant were added and ball milled for 1 hour. After 1 hour, 80 g of a wax binder was added and ball mill mixing was performed for 19 hours.

Next, 1.6 g of an amide defoaming agent was added to the slurry, and depressurization was carried out. The concentration of this slurry was 83%. This slurry was poured into a molding die having a molding size of 700 mm x 300 mm in the structure shown in FIG. 2, and drained at a reduced pressure of -760 mmHg to obtain a molded body. After drying the molded product, degreasing treatment was performed at 600 ° C for 3 hours. Thereafter, the mixture was calcined at 1550 ° C. for 8 hours in an oxygen atmosphere to obtain an ITO sintered body. The ITO sintered compact at this time was 578 mm x 247 mm x 6.9 mm, and the density of the sintered compact was 97.7% (6.99 g / cm <3>). The sintered compact had no defects such as cracks and cracks.

Example 9

7200 g of indium oxide powder having a specific surface area of 8.07 m 2 / g, 800 g of tin oxide powder having a specific surface area of 2.68 m 2 / g, and 240 g of ion-exchanged water were put together with a zirconia ball having a diameter of 5 mm into a resin pot for ball mill mixing for 20 hours. Next, 1440 g of ion-exchanged water and 64 g of a polycarboxylic acid dispersant were added and ball milled for 1 hour. After 1 hour, 80 g of a wax-based binder was added, followed by ball mill mixing for 19 hours.

Next, 1.6 g of an amide defoaming agent was added to the slurry, and depressurization was carried out. The concentration of this slurry was 83%. This slurry was poured into a molding die having a molding size of 700 mm x 800 mm in the structure shown in FIG. 2, and drained at a reduced pressure of -760 mmHg to obtain a molded body. After drying the molded product, degreasing treatment was performed at 600 ° C for 3 hours. Thereafter, the mixture was calcined at 1550 ° C. for 8 hours in an oxygen atmosphere to obtain an ITO sintered body. At this time, the ITO sintered compact was 578 mm x 247 mm x 7.3 mm, and the density of the sintered compact was 98.1% (7.01 g / cm <3>). The sintered compact had no defects such as cracks and cracks.

Example 10

6750 g of indium oxide powder having a specific surface area of 6.86 m 2 / g, 750 g of tin oxide powder having a specific surface area of 3.38 m 2 / g, and 225 g of ion-exchanged water were put together with a 5 mm diameter zirconia ball into a resin pot for ball mill mixing for 20 hours. Next, 1348.2 g of ion-exchanged water and 60 g of a polycarboxylic acid dispersant were added and ball milled for 1 hour. After 1 hour, 75 g of a wax-based binder was added and ball milled for 19 hours.

Next, 1.4 g of an amide defoaming agent was added to the slurry to depressurize the vacuum. The concentration of this slurry was 83%. This slurry was poured into a molding die having a molding size of 700 mm x 300 mm in the structure shown in FIG. 2, and drained at a reduced pressure of -760 mmHg to obtain a molded body. After drying the molded product, degreasing treatment was performed at 600 ° C for 3 hours. Thereafter, the mixture was calcined at 1550 ° C. for 8 hours in an oxygen atmosphere to obtain an ITO sintered body. At this time, the dimension of the ITO sintered compact was 565 mm x 242 mm x 7.1 mm, and the density of the sintered compact was 98.7% (7.05 g / cm <3>). The sintered compact had no defects such as cracks and cracks.

Example 11

7200 g of indium oxide powder having a specific surface area of 6.54 m 2 / g, 800 g of tin oxide powder having a specific surface area of 2.49 m 2 / g, and 240 g of ion-exchanged water were put together with a zirconia ball having a diameter of 5 mm into a resin pot for ball mill mixing for 20 hours. Next, 1440 g of ion-exchanged water and 64 g of a polycarboxylic acid dispersant were added and ball milled for 1 hour. After 1 hour, 80 g of a wax binder was added and ball milling was carried out for 19 hours.

Next, 1.6 g of an amide defoaming agent was added to the slurry, and depressurization was carried out. The concentration of this slurry was 83%. This slurry was poured into a molding die having a molding size of 700 mm x 300 mm in the structure shown in FIG. 2, and drained at a reduced pressure of -760 mmHg to obtain a molded body. After drying the molded product, degreasing treatment was performed at 600 ° C for 3 hours. Thereafter, the mixture was calcined at 1550 ° C. for 8 hours in an oxygen atmosphere to obtain an ITO sintered body. The ITO sintered compact at this time was 572 mm x 245 mm x 7.3 mm, and the density of the sintered compact was 98.6% (7.03 g / cm <3>). The sintered compact had no defects such as cracks and cracks.

Example 12

18000 g of indium oxide powder having a specific surface area of 6.64, 2000 g of tin oxide powder having a specific surface area of 3.11, 600 g of ion-exchanged water, and a zirconia ball having a diameter of 5 mm were placed in a resin pot for ball mill mixing for 20 hours.

Next, 3592 g of ion-exchanged water and 160 g of a polycarboxylic acid dispersant were added and ball milled for 1 hour. After 1 hour, 200 g of a wax-based binder was added and ball milled for 19 hours.

Next, 4 g of an amide defoaming agent was added to the slurry, and depressurization was carried out. The concentration of this slurry was 83%. This slurry was poured into a molding die having a molding size of 1270 mm x 375 mm in the structure shown in FIG. 2 and drained at a reduced pressure of -760 mmHg to obtain a molded product. The molded product was degreased at 600 ° C. for 3 hours after drying at 25 ° C., and fired at 1550 ° C. for 8 hours in an oxygen atmosphere to obtain an ITO sintered body. The dimension of the ITO sintered compact was 1046 mm x 308 mm x 7.9 mm, and the density of the sintered compact was 98.8% (7.06 g / cm <3>). A large ITO sintered body having a long axis of 1000 mm or more was obtained.

Comparative Example 3

900 g of indium oxide powder having a specific surface area of 4.22 m 2 / g, 100 g of tin oxide powder having a specific surface area of 2.2 m 2 / g, 7.9 g of an alcohol-based binder, and a zirconia ball having a diameter of 10 mm were placed in a resin pot for ball mill mixing for 20 hours. The treated powder was press molded at a molding size of 190 mm and a pressure of 1000 kgf / cm 2. The molded body was degreased at 600 ° C for 3 hours. The anti-stone strength after degreasing was 0.72 kgf / cm 2. The degreased molded body was calcined at 1550 ° C. for 8 hours in an oxygen atmosphere to obtain a high density ITO sintered body. The dimension of the ITO sintered compact was 166.0 mm x 5.7 mm, and the density was 99.0% (7.08 g / cm <3>).

Comparative Example 4

900 g of indium oxide powder having a specific surface area of 4.53 m 2 / g, 100 g of tin oxide powder having a specific surface area of 2.2 m 2 / g, 30 g of ion-exchanged water, and a zirconia ball having a diameter of 5 mm were placed in a resin pot and ball milled for 20 hours. Next, 128.7 g of ion-exchanged water and 4.5 g of a polycarboxylic acid dispersant were added and ball milled for 1 hour. After 1 hour, 9.9 g of a wax binder was added and ball milling was carried out for 19 hours.

Next, 0.4 g of an amide defoaming agent was added to the slurry to depressurize the vacuum. The concentration of this slurry was 86%. This slurry was poured into a molding die of a molding size of 190 mm ø of the structure shown in FIG. 1, and drained at a reduced pressure of -760 mmHg to obtain a molded body. The molded product was degreased at 600 ° C for 3 hours after drying at 25 ° C.

The anti-stone strength after degreasing was 0.60 kgf / mm 2. The degreased molded body was calcined at 1550 ° C. for 8 hours in an oxygen atmosphere to obtain an ITO sintered body. The dimension of the IT0 sintered compact was 160.6 mm x 5.9 mm, and the density was 99.7% (7.13 g / cm <3>).

Comparative Example 5

900 g of indium oxide powder having a specific surface area of 4.22 m 2 / g, 100 g of tin oxide powder having a specific surface area of 2.2 m 2 / g, 30 g of ion-exchanged water, and a zirconia ball having a diameter of 5 mm were placed in a resin pot for ball mill mixing for 20 hours. Next, 108.9 g of ion-exchanged water and 4.7 g of a polycarboxylic acid dispersant were added and ball milled for 1 hour. After 1 hour, 7.9 g of wax-based binder was added, followed by ball mill mixing for 19 hours.

Next, 0.5 g of an amide defoaming agent was added to the slurry to depressurize the vacuum. The concentration of this slurry was 87%. This slurry was poured into a molding die of a molding size of 190 mm ø of the structure shown in FIG. 1, and drained at a reduced pressure of -760 mmHg to obtain a molded body. The molded product was degreased at 600 ° C for 3 hours after drying at 25 ° C. The anti-stone strength after degreasing was 0.50 kgf / mm 2. The degreased molded body was calcined at 1550 ° C. for 8 hours in an oxygen atmosphere to obtain an ITO sintered body. The dimension of the ITO sintered compact was 166.0 mm * 5.5 mm, and the density was 99.9% (7.14 g / cm <3>).

Comparative Example 6

7200 g of indium oxide powder having a specific surface area of 14.7 m 2 / g, 800 g of tin oxide powder having a specific surface area of 2.482 m 2 / g, and 240 g of ion-exchanged water were put together with a zirconia ball having a diameter of 5 mm in a resin pot and ball milled for 20 hours.

Next, 2000 g of ion-exchanged water and 64 g of a polycarboxylic acid dispersant were added and ball milled for 1 hour. After 1 hour, 80 g of a wax binder was added and ball mill mixing was performed for 19 hours.

Next, 1.6 g of an amide defoaming agent was added to the slurry, and depressurization was carried out. The concentration of this slurry was 76%. This slurry was poured into a molding die having a molding size of 700 mm x 300 mm having the structure shown in FIG. 1, and drained at a reduced pressure of -760 mmHg to obtain a molded body. After drying the molded product, degreasing treatment was performed at 600 ° C for 3 hours. Thereafter, the mixture was calcined at 1550 ° C. for 8 hours in an oxygen atmosphere to obtain an ITO sintered body. The ITO sintered compact at this time was 522 mm x 224 mm x 7.1 mm, and the density of the sintered compact was 98.5% (7.04 g / cm <3>). Six cracks of 10 mm to 20 mm occurred in the sintered body.

Comparative Example 7

7200 g of indium oxide powder having a specific surface area of 7.73 m 2 / g, 800 g of tin oxide powder having a specific surface area of 7.62 m 2 / g, and 400 g of ion-exchanged water were added together with a zirconia ball having a diameter of 5 mm into a resin pot for ball mill mixing for 20 hours. Next, 1440 g of ion-exchanged water and 80 g of a polycarboxylic acid dispersant were added and ball milled for 1 hour. After 1 hour, 80 g of a wax binder was added and ball mill mixing was performed for 19 hours.

Next, 1.6 g of an amide defoaming agent was added to the slurry, and depressurization was carried out. The concentration of this slurry was 82%. This slurry was poured into a molding die having a molding size of 700 mm x 300 mm having the structure shown in FIG. 1, and drained at a reduced pressure of -760 mmHg to obtain a molded body. After drying the molded product, degreasing treatment was performed at 600 ° C for 3 hours. Thereafter, the mixture was calcined at 1550 ° C. for 8 hours in an oxygen atmosphere to obtain an ITO sintered body. At this time, the dimension of the ITO sintered compact was 575 mm x 246 mm x 7.4 mm, and the density of the sintered compact was 97.8% (6.99 g / cm <3>). Nineteen cracks having a length of 4 to 26 mm occurred in the sintered body.

Comparative Example 8

8100 g of indium oxide powder having a specific surface area of 7.73 m 2 / g, 900 g of tin oxide powder having a specific surface area of 7.23 m 2 / g, and 450 g of ion-exchanged water were put together with a zirconia ball having a diameter of 5 mm into a resin pot for ball mill mixing for 20 hours. Next, 1710 g of ion-exchanged water and 94 g of a polycarboxylic acid dispersant were added and ball milled for 1 hour. After 1 hour, 90 g of a wax-based binder was added, followed by ball mill mixing for 19 hours. The concentration of this slurry was 81%. This slurry was poured into a molding die having a molding size of 700 mm x 300 mm having the structure shown in FIG. After drying the molded product, degreasing treatment was performed at 600 ° C for 3 hours. The density after degreasing was 63% (4.5 g / cm 3). The molded body was divided into two at the center by degreasing.

Comparative Example 9

8100 g of indium oxide powder having a specific surface area of 4.53 m 2 / g, 900 g of tin oxide powder having a specific surface area of 2.68 m 2 / g, and 270 g of ion-exchanged water were put together with a 5 mm diameter zirconia ball into a resin pot for ball mill mixing for 20 hours. Next, 1170 g of ion-exchanged water and 41 g of a polycarboxylic acid-based dispersant were added thereto, followed by ball milling for 1 hour. After 1 hour, 90 g of a wax-based binder was added, followed by ball mill mixing for 19 hours.

Next, 4.5 g of an amide defoaming agent was added to the slurry, and degassing was carried out. The concentration of this slurry was 86%. This slurry was poured into a molding die having a molding size of 700 mm x 300 mm having the structure shown in FIG. 1, and drained at a reduced pressure of -760 mmHg to obtain a molded body. After drying the molded product, degreasing treatment was performed at 600 ° C for 3 hours. Thereafter, the mixture was calcined at 1550 ° C. for 8 hours in an oxygen atmosphere to obtain an ITO sintered body. The dimension of the IT0 sintered compact at this time was 593 mm x 254 mm x 7.7 mm, and the density of the sintered compact was 98.6% (7.05 g / cm <3>). A crack of 20 mm occurred in the sintered body.

Comparative Example 10

7200 g of indium oxide powder having a specific surface area of 4.50 m 2 / g, 800 g of tin oxide powder having a specific surface area of 7.62 m 2 / g, and 240 g of ion-exchanged water were put together with a zirconia ball having a diameter of 5 mm into a resin pot and ball milled for 20 hours. Next, 1440 g of ion-exchanged water and 64 g of a polycarboxylic acid dispersant were added and ball milled for 1 hour. After 1 hour, 80 g of a wax-based binder was added and ball milled for 19 hours.

Next, 1.6 g of an amide defoaming agent was added to the slurry, and depressurization was carried out. The concentration of this slurry was 83%. This slurry was poured into a molding die having a molding size of 700 mm x 300 mm having the structure shown in FIG. 1, and drained at a reduced pressure of -760 mmHg to obtain a molded body. After drying the molded product, degreasing treatment was performed at 600 ° C for 3 hours. Thereafter, the mixture was calcined at 1550 ° C. for 8 hours in an oxygen atmosphere to obtain an ITO sintered body. The ITO sintered compact at this time was 588 mm x 251 mm x 7.1 mm, and the density of the sintered compact was 97.9% (7.00 g / cm <3>). Cracks of 12 mm and 17 mm occurred in the sintered body.

Comparative Example 11

8100 g of indium oxide powder having a specific surface area of 3.68 m 2 / g, 900 g of tin oxide powder having a specific surface area of 2.65 m 2 / g, and 270 g of ion-exchanged water were put together with a zirconia ball having a diameter of 5 mm into a resin pot and ball milled for 20 hours. Next, 1170 g of ion-exchanged water and 41 g of a polycarboxylic acid-based dispersant were added thereto, followed by ball milling for 1 hour. After 1 hour, 90 g of a wax-based binder was added, followed by ball mill mixing for 19 hours.

Next, 4.5 g of an amide defoaming agent was added to the slurry, and degassing was carried out. The concentration of this slurry was 86%. This slurry was poured into a molding die having a molding size of 700 mm x 300 mm having the structure shown in FIG. After drying the molded product, degreasing treatment was performed at 600 ° C for 3 hours. Thereafter, the mixture was calcined at 1550 ° C. for 8 hours in an oxygen atmosphere to obtain an IT0 sintered body. The ITO sintered compact at this time was 597 mm x 255 mm x 7.5 mm, and the density of the sintered compact was 98.6% (7.05 g / cm <3>). The crack of 15 mm generate | occur | produced in the sintered compact.

Table 2 shows the specific surface area of indium oxide and the anti-theft strength of the ITO target under conditions in which the specific surface area of tin oxide is fixed. In the case where the specific surface area of indium oxide is the same, the ITO molded body formed by the filtration molding method has a lower anti-calcite strength as compared to the press molded ITO molded body. However, by increasing the specific surface area of indium oxide, it is possible to increase the strength of the stone.

Specific Surface Area and Strength of Indium Oxide Yes Specific surface area (㎡ / g) 25 ℃ drying (kgf / mm2) 600 ℃ degreasing (kgf / mm2) Example 7 8.07 0.27 0.94 Comparative Example 3 (Press Molding) 4.22 0.35 0.72 Comparative Example 4 4.53 0.20 0.60 Comparative Example 5 4.22 0.31 0.50

In Table 3, the density and the presence or absence of the defect of the ITO molded object shape | molded at 700 mm x 300 mm in internal dimension are shown. If the specific surface area of the used indium oxide and tin oxide raw material powder deviates from the range defined in the present invention, defects such as cracking and degreasing cracking occur.

Density of ITO Molded Body Yes Indium oxide (㎡ / g) Tin oxide (㎡ / g) Molding density% Plastic density% flaw Example 8 8.52 2.95 60.0 97.7 radish Example 9 8.07 2.68 60.1 98.1 radish Example 10 6.86 3.38 56.0 98.7 radish Example 11 6.54 2.49 54.9 98.6 radish Comparative Example 6 14.7 2.48 50.24 98.5 crack Comparative Example 7 7.73 7.62 59.2 97.8 crack Comparative Example 8 7.73 7.23 63.0 - Skim cracking Comparative Example 9 4.53 2.68 63.7 98.6 crack Comparative Example 10 4.50 7.62 61.8 97.6 crack Comparative Example 11 3.68 2.65 63.6 98.6 crack

As described above, as shown in Examples 7 to 12 and Comparative Examples 3 to 11, according to the present invention, by selecting the specific surface area of the raw material powder of indium oxide and tin oxide in a specific range, it is large and free of defects compared with the conventional one. An IT0 sintered body is obtained.

By using the filtration type mold of the present invention, since the molded body is manufactured by a filtration method in which the water in the slurry is drained under reduced pressure only on one side, there is a defect such as density unevenness or compositional unevenness inside the molded body due to hardening in one direction. Does not occur. Moreover, the molded object with a thickness difference can be obtained by using the filtration type shaping | molding die of this invention.

In addition, in the conventional press molding or pressurization, it is necessary to increase the equipment strength of the molding member, the press machine, etc. according to the increase in the molding size, and the equipment cost becomes expensive. Since only the lower mold is applied, a material having a relatively low strength can be used as the lower mold for molding, and the material cost can be reduced even if the molding size is increased.

According to the shaping | molding method using the filtration shaping | molding die of this invention, by selecting the specific surface area of the raw material powder of indium oxide and tin oxide in an appropriate range, the high density ITO sintered compact which is large compared and the defect free compared with the past is obtained.

Claims (8)

A filter type mold comprising a water-insoluble material for obtaining a ceramic molded body by draining water from a ceramic raw material under reduced pressure, comprising: a lower mold for molding having at least one water drain hole, a filter having water permeability placed on the lower mold for molding; Consists of a molding die frame to be inserted from the upper surface side through the sealing material for sealing the filter, the lower mold, the molding frame, the sealing material and the filter is assembled so as to disassemble each, and the slurry only on the filter surface side Filtration shaping | molding type | mold which drains water in a vacuum under reduced pressure. The filter type mold according to claim 1, wherein the filter face side of the lower mold for molding has an uneven shape. A slurry composed of ceramic raw material powder, ion-exchanged water and an organic additive is prepared, and the slurry is injected into the filter forming mold according to claim 1, and the water in the slurry is drained under reduced pressure only at the filter surface to produce a molded product. And calcining the obtained ceramic molded body after dry degreasing. A slurry composed of ceramic raw material powder, ion-exchanged water and an organic additive is prepared, and the slurry is injected into the filter forming mold according to claim 2, and the water in the slurry is drained under reduced pressure only on the filter side to produce a molded article. And calcining the obtained ceramic molded body after dry degreasing, wherein the ceramic sintered body having a thickness difference is produced. A slurry composed of indium oxide powder, tin oxide powder, ion-exchanged water, and an organic additive is prepared, and the slurry is poured into the filtration type mold according to claim 1, and the water in the slurry is drained under reduced pressure only on the filter surface side to form a molded article. The method for producing a high purity ITO sintered compact, which is prepared and fired after drying degreasing the obtained ITO molded body. A slurry composed of indium oxide powder, tin oxide powder, ion-exchanged water, and an organic additive is prepared, and the slurry is poured into the filtration type mold according to claim 2, and the water in the slurry is drained under reduced pressure only at the filter face to form a molded article. A method for producing an ITO sintered compact having a thickness difference, wherein the obtained ITO compact is baked after dry degreasing. The method for producing an ITO sintered compact according to claim 5 or 6, wherein the specific surface area of the indium oxide powder is 4.6 m 2 / g or more and 14.6 m 2 / g or less, and the specific surface area of the tin oxide powder is 7.2 m 2 / g or less. . An ITO sintered compact having a relative density of 97.5% (density 6.97 g / cm 3) or more obtained by firing an ITO molded article produced by the method according to claim 7 in an oxygen atmosphere after drying.