JP2000169241A - Binder, ceramic slurry by using the same, and production of ceramic sintered compact - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a ceramic sintered compact from generation of breakage and warpage even if a degreasing treatment is carried out in a short time by mixing an organic binder or an inorganic binder with powder of a ceramic raw material and water, casting the obtained slurry, heating and hardening the cast product to provide a compact, and degreasing and baking the obtained compact. SOLUTION: An organic binder material selected from a paraffin-based binder, a resin-based binder and a wax-based binder, or an inorganic binder selected from a phosphoric acid-based binder, a silicon-based binder and a titanium-based binder is used. The binder is mixed with powder of a ceramic raw material, and water to provide a ceramic slurry. The obtained slurry is cast in a casting mold, and heated and hardened in the mold. The obtained compact is subjected to a degreasing treatment and thereafter subjected to a baking treatment. The ceramic slurry enables a highly accurate forming such as casting molding, injection molding and gel-casting molding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a binder used for molding a ceramic raw material powder, and a ceramic slurry using the same.

[0002]

2. Description of the Related Art Heretofore, when firing a ceramic as an electronic component, the ceramic has been mounted on a setter made of a heat-resistant ceramic material such as alumina and fired.

[0003] As a method of manufacturing the setter used here, a binder is mixed with the raw material powder of the setter to form a mixed powder, which is formed into a desired shape by a pressure press, or water is added to the mixed powder. Casting and dewatering as ceramic slurry. The formed body obtained by such a method is subjected to a degreasing treatment in a firing furnace to heat and disperse the binder component in the formed body, and then subjected to a firing treatment to sinter the formed body to form a setter.

In general, the thicker the setter is, the larger the heat capacity of the setter becomes, and the lower the temperature followability of the work placed on the setter becomes. Therefore, the thinner the setter is, the better. However, it is difficult to form a setter having a thickness of 3 mm or less by the above-described molding method. Therefore, the molding of the setter is performed using a molding method in which the ceramic slurry is cast into a mold that can be easily molded even with a thin setter and cured.

[0005] As a binder added to the ceramic slurry or the mixed powder, an organic binder such as an epoxy resin, a urethane resin and an amide resin is usually used.

[0006]

However, when firing a molded article, a degreasing treatment for heating and dispersing a binder in the molded article is required. If the degreasing treatment is insufficient or if the degreasing temperature is rapidly increased, it may cause deterioration of mechanical properties, cracks or warpage. Therefore, in the conventional degreasing process, the degreasing temperature must be slowly increased, and there is a problem that productivity is poor because the degreasing process takes a long time.

[0007] It is an object of the present invention to provide a binder and a ceramic slurry which do not cause cracking or warping even when degreasing is performed in a short time.

[0008]

The present invention has been made in view of the above problems. The binder of the first invention is an organic binder material selected from a paraffin binder material, a resin binder material, and a wax binder material, and an inorganic binder selected from a phosphoric acid binder material, a silicon binder material, and a titanium binder material. And a material.

A ceramic slurry according to a second aspect of the present invention is characterized in that the binder according to the first aspect, a ceramic raw material powder, and water are mixed.

[0010] By molding in such a configuration, even if the degreasing treatment is performed in a short time, it is possible to prevent the molded article from cracking or warping. That is, before the degreasing, the strength of the molded body is maintained by the organic binder material, and when the organic binder material is heated and dispersed by the degreasing, the inorganic binder material maintains the strength of the molded body. Can be difficult. In addition, high-precision molding such as casting and injection molding can be performed.

Further, a method for producing a sintered body according to a third aspect of the present invention includes:
(1) a step of casting the ceramic slurry according to the second invention into a mold, (2) a step of heating and curing the ceramic slurry in the mold to form a molded body, and (3) a step of molding the molded body. And a baking process after the degreasing process.

By having such a step, a thin-walled molded article or a molded article having a complicated shape can be obtained.
In addition, a molded body having a short degreasing time can be obtained.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The binder of the present invention comprises an organic binder selected from a paraffin binder, a resin binder and a wax binder, a phosphoric binder, a silicon binder and a titanium binder. And an inorganic binder material selected from materials.

Further, the binder is added to the ceramic raw material powder, and water is further added to form a ceramic slurry.

Among the organic binder materials used in the binder of the present invention, examples of the paraffin binder material include polyvinyl alcohol, polyvinyl butyral, polyethylene glycol, methyl cellulose, ethyl cellulose and the like.

[0016] Among the organic binder materials, resin binder materials include polyethylene resin, vinyl acetate resin, epoxy resin, melamine resin, styrene resin, polyacetal resin, polyester resin, polypropylene resin, vinyl chloride resin, acrylic resin and polyamide. Resins, urethane resins and the like.

Further, among the organic binder materials, wax-based binder materials include paraffin wax, microsterin wax, Fischer-Tropsch wax,
Examples include polyethylene wax, modified wax, and tactic polypropylene.

Further, among the inorganic binder materials used in the binder of the present invention, the phosphoric acid binder material is
Examples include phosphoric acid, aluminum phosphate, pyrophosphoric acid, and tripolyacid.

Among the inorganic binder materials, the silicon-based binder materials include sodium silicate and Frogme clay.

Further, among the inorganic binder materials, the titanium-based inorganic binder includes titania sol and the like.

In the ceramic slurry of the present invention, the addition ratio of the organic binder material and the inorganic binder material is not particularly limited as long as a molded body can be obtained. In order to maintain mechanical strength, the inorganic binder material is preferably used in an amount of 20 parts by weight or less based on 100 parts by weight of the ceramic raw material powder.

The ceramic raw material powder used in the ceramic slurry of the present invention may be alumina, zirconia,
There is no particular limitation as long as it has heat resistance, such as mullite, silicon carbide, silicon nitride, etc., but it is preferable to use alumina because it is excellent in strength and inexpensive.

Next, the present invention will be described more specifically based on examples.

[0024]

Example 1 First, a low soda alumina powder (D ₅₀ = 1 μm) was prepared as a ceramic raw material powder.
Epoxy resin is added to this alumina powder as a resin-based organic binder material, and then Frogme clay and water are added as a silicic acid-based inorganic binder material so that the viscosity becomes 0.5 ± 0.01 Pa · s. Mix in a mill for 10 minutes,
A ceramic slurry was obtained.

Next, the obtained ceramic slurry was poured into a predetermined mold and thermally cured at 90 ° C. for 1 hour to obtain a molded body. This molded body is heated to 600 ° C. at 4 ° C./hr after 200 ° C.
Up to 100 hours for degreasing,
Sintering was performed at 600 ° C. for 2 hours to obtain a sintered body.

Among the molded articles obtained as described above,
Using a test piece molded into a size of 3 × 4 × 40 (mm), a degreasing treatment was performed in the same manner as described above, and the strength of the molded body was measured. Table 1 shows the results. In addition, what did not add the frog eye clay was prepared as a comparative example.

[0027]

[Table 1]

As shown in Table 1, it can be seen that the one using epoxy resin and Frogme clay as the binder has improved the strength of the molded body after degreasing.

Example 2 The strength of the molded body after degreasing was measured in the same manner as in Example 1 except that the types of the organic binder material and the inorganic binder material used for the molded body of Example 1 were changed.
Table 2 shows the results.

[0030]

[Table 2]

As shown in Table 2, even when the organic binder material and the inorganic binder material were changed, the strength of the molded body after degreasing was improved as in Example 1.

Example 3 Sample No. 4 used in Example 1
The shape of the molded body was set to 200 × 200 × 5 (mm), and the temperature was gradually increased in a short time from 200 to 400 ° C., which is the temperature at which the epoxy resin decomposes, to perform degreasing treatment. The defective rate such as chipping was measured. Table 2 shows the results. The comparative example was the same as that used in Example 1, and the size of the molded body was the same as that of the molded body used in this example.

[0033]

[Table 3]

As shown in Table 3, compared with the conventional molded body,
It can be seen that even if the time required for the degreasing treatment is shortened to some extent, no defects are observed in the molded body.

[0035]

The binder of the present invention is selected from organic binder materials selected from paraffin-based binder materials, resin-based binder materials, and wax-based binder materials, and phosphoric acid-based binder materials, silicon-based binder materials, and titanium-based binder materials. The ceramic slurry of the present invention contains the binder, the ceramic raw material powder, and water. Therefore, even if the degreasing treatment is performed in a short time, it is possible to prevent the molded body from cracking or warping. In addition, high-precision molding such as casting, injection molding, and gel casting can be performed.

The method for producing a sintered body of the present invention
(1) a step of casting the ceramic slurry according to the second invention into a mold, (2) a step of heating and curing the ceramic slurry in the mold to form a molded body, and (3) a step of molding the molded body. After the degreasing treatment, the firing step is performed, so that a thin-walled molded article or a molded article having a complicated shape can be obtained, and a molded article having a short degreasing time can be obtained.

Claims (3)

[Claims] An organic binder material selected from a paraffin-based binder material, a resin-based binder material, and a wax-based binder material; an inorganic binder material selected from a phosphoric-acid-based binder material, a silicon-based binder material, and a titanium-based binder material; The binder characterized by containing. 2. A ceramic slurry obtained by mixing the binder according to claim 1, a ceramic raw material powder, and water. 3. A step of casting the ceramic slurry according to claim 2 into a mold; and (2) a step of heating and curing the ceramic slurry in the mold to form a ceramic molded body. And baking the molded body after degreasing the molded body.