JPH01176508A - Centrifugal cast molding method for multi-layer ceramic molded material - Google Patents

Abstract

PURPOSE:To form a multi-layered wall layer by casting two kinds or more of ceramic sludge in a specified order into a gypsum mold revolving by means of a shaft as its revolution center and wall gradually on the inner surface of gypsum mold under the action of centrifugal force. CONSTITUTION:A gypsum mold 20 is fitted in an outer frame 10 and revolution moment with a shaft core as its revolution center is given by revolving rollers 40, 40. sludge for an external layer is cast in said gypsum mold 20. The cast sludge for an external layer forms a sludge layer along the inner surface of the gypsum mold 20 under the action of centrifugal force generated by the revolution of the gypsum mold 20, and water absorbed by the gypsum mold 20 to wall the inner surface of the gypsum mold 20 from a wall layer 1 for the outer layer. Then, a wall layer 2 as an internal layer is lamination formed by casting the sludge for forming the internal layer on the inner surface of the wall layer 1. Thus, the two wall layers 1 and 2 are released out of the gypsum mold 20 after being formed, dried and calcined.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for centrifugal molding of a hollow ceramic molded body having a concentric multilayer laminated structure.

[Conventional technology]

As a method for manufacturing a ceramic molded body with a multilayer structure consisting of a plurality of layers with different particle size structure, porosity, or ceramic type, etc., a ceramic molded body with a single layer structure is manufactured, and then the molded body is separately manufactured. A method of depositing a layer of slurry on the surface of a molded body by immersing it in prepared ceramic mud, or a method of placing multiple ceramic kneaded materials prepared according to the number of layers of the desired multi-layered molded body into a press mold. A method is known in which the material is filled in layers and then pressure molded.

[Problem that the invention seeks to solve]

However, in the method of forming a multilayer structure by depositing ceramic slurry in layers on the surface of a molded article having a layered structure, the process of depositing the slurry and drying the deposited layers is repeated as many times as the number of layers of the desired laminated structure. - Since firing must be repeated, the process becomes complicated and costs increase. Furthermore, it is difficult to form a relatively thick inlay layer.

On the other hand, the method of filling a press mold with a plurality of ceramic kneaded materials in a layered manner and press-forming has the advantage that a molded product with the desired multilayer structure can be obtained in the press-forming and firing steps. However, there are restrictions on the shape of the molded body that can be manufactured, and for example, it is not possible to obtain a hollow molded body having a concentric multilayer structure.

The present invention provides a method for centrifugal casting of ceramic molded bodies to solve the above-mentioned problems.

[Means and effects for solving the problems] The first method of centrifugal casting of a ceramic molded body according to the present invention is as follows:
Inside a gypsum mold that rotates around its axis, ceramic particles with different particle sizes, types, or additives are placed.
The method is characterized in that more than one type of ceramic plaster is cast in a predetermined order, and each type of plaster is sequentially deposited on the inner surface of the plaster mold under the action of centrifugal force. In addition, the second method of the present invention involves casting a ceramic slurry containing ceramic adjusted to a desired particle size distribution or two or more types of ceramics with different specific gravities mixed at a desired blending ratio, and applying centrifugal force. It is characterized by depositing plaster on the inner surface of the plaster mold under the action of.

The present invention will be explained in detail below.

First, when forming a multilayer laminated ceramic molded body by the first method of the present invention, ceramic slurry is prepared for each layer depending on the number of layers of the intended ceramic molded body and desired characteristics for each layer. For example, when forming a two-layer ceramic molded body in which the outer layer is made of coarse ceramic particles and the inner layer is made of fine ceramic particles, use a ceramic slurry in which coarse ceramic particles are suspended to form the outer layer. , and a slurry for forming the inner layer, in which fine ceramic particles are suspended, are prepared and centrifugally cast.

FIG. 1 shows an example of the centrifugal casting machine. (2
0) is a gypsum mold, and the gypsum mold (20
) is fitted into the outer frame (lO), and end plates (30,
30) is fitted, and the rotary drive roller (30°30
), and is rotated by rotationally driven rollers (40, 40), which provide a rotational movement about its own axis. Inside this plaster mold (20), there is a hopper (5
0), first pour the slurry for the outer layer. The cast plaster for the outer layer forms a slurry layer along the inner surface of the plaster mold (20) under the action of centrifugal force due to the rotation of the plaster mold (20), and receives the water absorption action of the plaster mold (20). By applying ink to the inner surface of the gypsum mold (20), an ink layer (1) serving as an outer layer is formed. Next, when an inner layer forming slurry is cast on the inner surface of the inking layer (1), a layer of inner layer sludge is formed along the inner circumferential surface of the inking layer (1) due to the action of centrifugal force, and the inking layer (1) is coated. By receiving the water absorption action of the gypsum mold (20) through the flesh layer (1), a flesh layer (2) which becomes an inner layer is formed on the inner surface of the flesh layer (1).
are formed in layers.

After forming the two ink layers (1) and (2) in this way,
By removing the mold from the gypsum mold (20), drying and firing, a fired product of a hollow ceramic ink molded body having a two-layer stack with an inner layer and an outer layer having different particle size structures is obtained.

In addition, when manufacturing a two-layer ceramic ink molded body in which the outer layer and the inner layer have different porosities for use in filters, etc., use slurry with different particle size compositions of the ceramic ink as described above. By forming two inking layers, each layer has different grain size structure.
porosity. In this case, if an appropriate pore-forming agent according to the desired porosity, for example, a burning substance such as carbon particles, is added to each slurry for forming each inking layer, it is possible to By burning and extinguishing the scorched material in the process, it is possible to provide each layer with a porosity of any height depending on the blending ratio of the scorched material.

Furthermore, depending on the intended use of the two-layer ceramic molded body and the required material properties, different types of ceramics, such as a slurry containing oxide-based ceramic particles or a slurry containing carbide-based ceramic particles, may be used. By performing centrifugal molding in the same manner as above, it is possible to obtain a two-layer ceramic molded body having a layer made of oxide ceramic and a layer made of carbide ceramic.

In preparing the ceramic slurry for forming each layer, for example, by selecting the particle size and type of the ceramic, and adjusting the use or non-use of additives such as pore-forming agents and the mixing ratio, for example, A two-layer ceramic molded body having an outer layer and an inner layer with different particle sizes and materials, or an outer layer and an inner layer with different porosity and materials is obtained.

In the above explanation, a two-layer ceramic molded body was taken as an example, but by preparing three or more types of ceramic mud as desired and repeating the casting and inlaying of each mold according to a predetermined order, any desired shape can be formed. A multilayer ceramic molded body having several layers can be obtained.

Next, a second centrifugal casting method of the present invention will be explained. According to this centrifugal casting method, a hollow ceramic molded body having a multilayer structure can be obtained by performing mud casting twice. The ceramic slurry used in this centrifugal casting is prepared in accordance with the desired multilayer structure of the ceramic molded body. For example, when manufacturing a two-layer ceramic molded body with an outer layer made of coarse ceramic particles and an inner layer made of fine ceramic particles, a slurry in which coarse ceramic particles and fine ceramic particles are mixed and suspended is used. used. If the plaster is poured into a plaster mold and a plaster layer is formed along the inner circumferential surface of the plaster mold under the action of centrifugal force, the suspended particles in the plaster layer will be dispersed according to Kusu's theorem. Coarse particles migrate to the outer circumference side far from the rotation center, and fine particles migrate to the inner circumference side closer to the rotation center, agglomerate, and ink adhesion progresses, and as a result, ink is deposited inside the gypsum mold (20). An outer inlay layer (1) in which coarse-grained ceramic particles are aggregated and an inlay layer (2) in which fine-grained ceramic particles are aggregated are laminated. Then, this is removed from the gypsum mold (20) and subjected to drying and firing treatment to obtain a two-layer laminated ceramic molded body. In addition, when using slurry in which ceramic particles with a wide particle size distribution ranging from fine to coarse particles are used, the slurry has a particle orientation in which the particle size changes sequentially from the outer circumferential surface to the inner circumferential surface. A ceramic molded body is obtained. Furthermore, in the preparation of ceramic slurry,
When two or three or more types of ceramics with different specific gravity are used as a mixture, an adhesive layer is formed with particle orientation based on the difference in specific gravity, resulting in ceramic molding with a multilayer structure made of different types of ceramics. You can get a body. In preparing these slurries,
It goes without saying that a pore-forming agent and other various additives may be added as necessary.

[Effects of the Invention] According to the method of the present invention, a multilayer inlay can be formed by a series of casting steps of one type of ceramic slurry or two or more types of ceramic slurry, and after demolding, one layer is formed. It is possible to finish a fired product with a multi-layered structure through multiple drying and firing processes, which is different from the conventional mud immersion method, which requires repeating drying and firing each time each layer is formed. It is extremely simple and highly productive. In addition, unlike the press molding method, it is possible to easily form a cylindrical multilayer laminate, and due to the uniform action of centrifugal force, it has excellent homogeneity in the longitudinal direction, and there is little residual strain, etc., and the multilayer structure has good dimensional accuracy. A laminated molded product can be obtained.

Therefore, the method of the present invention is useful as a method for manufacturing hollow ceramic molded bodies used as filter materials, pipe materials, and various other structures.

[Brief explanation of the drawing]

FIG. 1 is an axial sectional view showing an embodiment of the method of the present invention. 1.2 Second flesh layer, 10: Outer frame, 20: Gypsum mold,
4o, 4o: rotary drive wheel, 50: slurry casting hopper.

Claims (2)

[Claims] (1) Two or more types of ceramic slurry with different ceramic particle sizes, types, or additives are cast in a predetermined order into a gypsum mold that rotates around its axis, and centrifugal force is applied to the mold. A centrifugal molding method for a hollow ceramic molded body having a multilayer structure, characterized by sequentially depositing each slurry on the inner surface of a gypsum mold. (2) Ceramic mud containing ceramics adjusted to a desired particle size distribution, or two or more types of ceramics with different specific gravity mixed in a desired proportion, in a gypsum mold that rotates around the axis. A method for centrifugal molding of a hollow ceramic molded body having a multilayer structure, characterized by casting and depositing mud under the action of centrifugal force.