JPH09314539A - Preparation of ceramic slurry - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the reduction of deforming time by a method in which ceramic slurry containing a ceramic raw material as a main component is treated under reduced pressure and ultrasonic vibration. SOLUTION: For example, ceramic slurry 16 of a mixture of a ceramic raw material composed of Ni-Cu-Zn type ferrite raw material, a dispersant, a binder, water, and a defoaming agent is charged into a slurry tank 13. While the slurry 16 being agitated by an agitator 11, ultrasonic vibration is applied to the slurry tank 13 by an ultrasonic vibrator 12, and the pressure of a vacuum tank 15 in which the slurry tank 13 is placed is reduced by a pressure reducing apparatus 14 to defoam the slurry 16. In this way, the transfer speed and mixing speed of bubbles in the slurry 16 is increased to enlarge the probability of collision between bubbles and the defoaming agent so that the slurry can be defoamed in a short time, and the ceramic slurry of uniform dispersion by ultrasonic vibration.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a ceramic slurry used for forming a ceramic green sheet or casting.

[0002]

2. Description of the Related Art A conventional method for manufacturing a ceramic slurry of this type will be described with reference to FIGS.

As a conventional example 1, as shown in FIG. 2, there is a ceramic slurry manufacturing apparatus comprising a slurry tank 3 equipped with a stirring device 1 and a pressure reducing device 2. A ceramic slurry 4 in which a ceramic raw material, a binder, a solvent and the like are mixed is put into the slurry tank 3, and the pressure inside the slurry tank 3 is reduced by the pressure reducing device 2 while stirring by the stirring device 1 to defoam. A ceramic slurry 4 is obtained.

Further, as a conventional example 2, as shown in FIG. 3, there is a ceramic slurry manufacturing apparatus in which a depressurizing tank 5 equipped with a depressurizing device 2 accommodates a rotatable slurry tank 6 itself. . A method for defoaming the ceramic slurry 4 in the slurry tank 6 by introducing the ceramic slurry 4 into the slurry tank 6 and rotating the slurry tank 6 to lower the pressure in the decompression tank 5 by the decompression device 2. Is.

In addition to this, Japanese Patent Application Laid-Open No. 3-254905 discloses a method of defoaming a ceramic slurry in advance by vacuum defoaming and then ultrasonically vibrating the slurry tank.

[0006]

However, in the method for producing a ceramic slurry having such a structure, in the conventional examples 1 and 2, although the ceramic slurry is agitated, bubbles are entrained around the center of the agitating rotation. There was a problem that it could not be stirred uniformly. Further, there is a problem that the effect of breaking bubbles in the ceramic slurry is small and the time required for defoaming becomes long.

On the other hand, in Japanese Patent Laid-Open No. 3-254905, since the ultrasonic vibration treatment is performed after the vacuum defoaming treatment, the time required for ultrasonic vibration is required in addition to the time required for vacuum defoaming. There is a problem that the foam treatment time becomes long.

An object of the present invention is to solve the above-mentioned problems, and it is an object of the present invention to provide a method for producing a ceramic slurry which can greatly reduce the defoaming time.

[0009]

In order to achieve the above object, in the method for producing a ceramic slurry of the present invention, a slurry of ceramic slurry containing a ceramic raw material as a main component is depressurized and ultrasonically vibrated. Defoaming treatment is performed. It is preferable to perform defoaming treatment while further stirring the ceramic slurry.

As a result, the moving speed of the bubbles in the ceramic slurry is increased, and the precipitation of bubbles in the outside of the ceramic slurry and the breaking of bubbles are promoted. Further, the moving speed and the mixing speed of the bubbles in the ceramic slurry are increased, the collision probability of the bubbles and the defoaming agent is increased, and the effect of the defoaming agent is promoted. Therefore, the ceramic slurry can be defoamed in a short time, and the ceramic slurry uniformly stirred can be obtained by micro-mixing by ultrasonic vibration.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment according to the present invention will be described in detail with reference to FIG. The ceramic slurry manufacturing apparatus includes a stirring device 11 and
There is a slurry tank 13 having an ultrasonic vibration device 12 inside, and the slurry tank 13 is housed inside a decompression tank 15 equipped with a decompression device 14.

For example, a slurry-like ceramic slurry 16 in which a ceramic raw material made of a Ni-Cu-Zn ferrite raw material, a dispersant, a binder, water and a defoaming agent are added and mixed is put into a slurry tank 13. While stirring the ceramic slurry 16 with the stirring device 11, ultrasonic vibration is applied to the slurry tank 13 by the ultrasonic vibration device 12, and the inside of the decompression tank 15 accommodating the slurry tank 13 is decompressed by the decompression device 14. Then, the ceramic slurry 16 is defoamed.

The ceramic slurry 16 thus obtained was molded into a ceramic green sheet by the doctor blade method. Further, the ceramic green sheet was pressed and sintered to obtain a sintered body. Various performances of these ceramic slurries, ceramic green sheets and sintered bodies were evaluated. The results are shown in Table 1 as an example.

For comparison, a ceramic slurry, a ceramic green sheet and a sintered body were obtained under the same conditions as those of the examples except that no ultrasonic vibration was applied, and the same performance as the examples was evaluated. . The results are shown in Table 1 as a comparative example.

[0015]

[Table 1]

As is clear from Table 1, for the ceramic slurry, air bubbles disappeared on the surface of the ceramic slurry in the defoaming time of 10 minutes in the example, whereas in the comparative example, the defoaming time of 30 minutes was eliminated. However, the bubbles are not eliminated, and the defoaming time is greatly shortened in the embodiment.

Regarding the ceramic green sheet, the example is superior to the comparative example in terms of the number and density of pinholes. Further, regarding the sintered body, the example is superior to the comparative example in terms of the amount of pores and the initial magnetic permeability.

In the above-described embodiment, the ceramic slurry manufacturing apparatus has the stirring device 11, but the stirring device 11 can be omitted in the ceramic slurry that does not require macro stirring.

Also, with respect to the ultrasonic vibrating device, an example in which the ultrasonic vibrating device is mounted inside the slurry tank is shown, but a plurality of ultrasonic vibrating devices may be mounted outside the slurry tank, or the slurry tank itself is vibrated ultrasonically. However, it can be variously modified within the scope of the gist.

Further, the ceramic slurry according to the present invention is not limited to the above Ni-Cu-Zn type ferrite material, but may be applied to other magnetic materials, dielectric materials, insulator materials, semiconductor materials and the like. You can

[0021]

As described above, in the method for producing a ceramic slurry according to the present invention, the moving speed of the bubbles in the ceramic slurry is increased, and the deposition of bubbles to the outside of the ceramic slurry and the breaking of bubbles are promoted. , The defoaming time can be shortened. Further, the moving speed and the mixing speed of the bubbles in the ceramic slurry are increased, the collision probability between the bubbles and the defoaming agent is increased, and the effect of the defoaming agent is promoted, whereby the defoaming time can be shortened. Further, it is possible to obtain a uniformly stirred ceramic slurry by performing microscopic mixing by ultrasonic vibration.

Further, since the ultrasonic vibration is applied to the ceramic slurry while reducing the pressure, the defoaming device can be downsized.

[Brief description of drawings]

FIG. 1 is an illustrative view showing an apparatus for producing a ceramic slurry according to one embodiment of the present invention.

FIG. 2 is an illustrative view showing an apparatus for producing a ceramic slurry of Conventional Example 1.

FIG. 3 is an illustrative view showing an apparatus for producing a ceramic slurry of Conventional Example 2.

[Explanation of symbols]

 11 Stirrer 12 Ultrasonic Vibration Device 13 Slurry Tank 15 Decompression Tank 16 Ceramic Slurry

Claims (2)

[Claims] 1. A method for producing a ceramic slurry, which comprises defoaming a slurry-like ceramic slurry containing a ceramic raw material as a main component by depressurizing and ultrasonically vibrating. 2. The method for producing a ceramic slurry according to claim 1, wherein the ceramic slurry is subjected to defoaming treatment while being further stirred.