JPH05329814A - Method for molding inclination function material - Google Patents

Abstract

PURPOSE:To mold a thick-walled inclination function material from many kinds of raw materials continuously and smoothly inclined in its compsn. and having uniform density distribution without generating deformation in a baking process. CONSTITUTION:In a dehydrating and molding process wherein a slurry containing a raw material powder such as a ceramic raw material is supplied to a dehydrating and molding container 2 and dehydrated under pressure to be molded into a predetermined shape, the supplied slurry S1 is changed over to a slurry of a different kind on the way of the dehydrating and molding process and the compsn. of the slurry S1+2 stagnated in the dehydrating and molding container 2 is changed in a time series manner to continuously change the compsn. of a dehydrated molded object 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention cannot be obtained with a material having a uniform composition as a whole by changing the composition of a molded article such as a ceramic sheet according to its position (ie, grading the composition). The present invention relates to a method of molding a functionally gradient material capable of obtaining such characteristics.

[0002]

2. Description of the Related Art As a conventional method of molding a functionally gradient material, for example, two or more kinds of mixed raw material powders prepared by mixing plural kinds of raw material powders are prepared and There is a method of molding a functionally-graded material by throwing into a mold or the like to perform gradient filling and pressurizing to perform consolidation.

However, in the conventional method for forming a functionally gradient material, there is a problem in the uniform mixing property of the mixed raw material powder prepared by mixing the powders, which may cause compositional deviation. Also in the case of wet mixing, segregation of the composition may occur during drying.

Further, a portion (step) having a significantly different composition is formed in the gradient-filled portion, and the composition change (gradient) is stepwise, so that a molded body (gradient functional material) having an ideal composition gradient is obtained. There is a problem that you cannot do it.

Regarding the shape of the functionally gradient material to be molded, the pressure distribution becomes non-uniform in the step of compacting the powder when the thickness of the functionally graded material is increased, and the density of the inside (central portion) is reduced. Then, there is a problem that distortion occurs in the composition gradient.

The present invention is intended to solve the above-mentioned problems, in which the composition is continuously and smoothly inclined, the density distribution is uniform, and deformation does not occur in the firing process, and it is possible to obtain various thicknesses from various raw materials. An object of the present invention is to provide a method for forming a functionally gradient material, which is capable of molding a functionally gradient material for meat.

[0007]

In order to achieve the above object, a method of forming a functionally gradient material according to the present invention is such that a slurry containing a raw material powder such as a ceramic raw material is supplied to a dehydration forming container and is pressurized. In a series of dehydration molding steps of dehydration and molding into a predetermined shape, the slurry to be supplied is switched to a different type of slurry during the dehydration molding step, and the composition of the slurry retained in the dehydration molding container is time-sequentially. It is characterized in that the composition of the molded body to be dehydrated and molded is continuously changed by changing the composition.

[0008]

By changing the type of the slurry supplied to the dehydration molding container, slurries having different compositions are supplied to the dehydration molding container and mixed with the slurry before switching, which remains in the dehydration molding container, and dehydrates over time. Since the composition of the slurry staying in the molding container changes continuously and the composition changes smoothly with a predetermined slope without forming a step, the slurry staying in the dehydration molding container is dehydrated and molded The body composition also changes continuously and smoothly. Therefore, it becomes possible to reliably form a functionally graded material having no gradient distortion.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 4 are views showing an embodiment of a method for molding a functionally gradient material of the present invention.

In this embodiment, as shown in FIGS. 1 to 4, a dehydration molding container 2 having one surface formed of a filtration plate (filtration surface) 1 is used and contains a ceramic raw material powder. The slurries S ₁ and S ₂ are supplied by the following procedure,
Molded body (gradient functional material) 3 by dehydration molding
(FIG. 4) was molded.

[Slurry Supply Procedure] First, as shown in FIG. 1, a slurry S _{1 having a first} composition is used.
To fill the dehydration molding container 2. When dehydrated molded container 2 is filled with the slurry S _1, from the slurry S ₁ of the first composition the feed slurry, is supplied by switching to the slurry S ₂ of the second composition, the molded body to dehydration molding container 2 (Cake Layer 3 is molded (FIG. 2). Then, by continuously supplying the slurry S _{2 having} the second composition, the compact 3 is grown (FIG. 3). The slurry S ₂ is supplied until the dehydration molding container 2 is filled with the molding 3 to mold the molding 3 having a shape corresponding to the internal shape of the dehydration molding container 2 (FIG. 4).

Next, the changes in the composition of the slurry and the molding process of the functionally gradient material (molded body) in each step of the above-mentioned embodiment will be described step by step.

First, when the dehydration molding container 2 is filled with the slurry S ₁ in the above process, the particles (ceramic raw material powder) in the slurry S ₁ are freely flowing. FIG. 5 is a diagram schematically showing this state. In FIG. 5, 11 is ceramic raw material particles and 12 is a solvent (water).
Is shown.

[0014] When the slurry S ₂ of the second composition in the steps described above is supplied, the slurry S ₂ is the pressure medium, pressure is applied to the slurry S ₁ of dehydration molding container 2, filter surface 1 Dewatering from the membrane and infiltration (adhesion of a cake layer made of ceramic raw material powder) onto the filtration surface 1 start, and particles (ceramic raw material powder) are arranged on the filtration surface 1 to form a molded body (cake layer) 3. It is gradually formed (Fig. 2).
FIG. 6 is a diagram schematically showing this state, where 11 is ceramic raw material particles and 12 is a solvent (water).

When the slurry S ₂ having the second composition is continuously supplied in the steps 1 to 3, the slurry staying in the dehydration molding container 2 becomes the slurry S _{1 having} the first composition.
When the second mixed slurry S ₂ of the composition slurry S _{1 + 2} (Fig. 3), and the time series change its composition corresponds to the supply amount of the slurry S ₂ of the second composition, and finally Immediately before the inside of the dehydration molding container 2 is filled with the molded body 3, it has substantially the same composition as the slurry S ₂ of the second composition.

Therefore, the first molded part of the molded body 3 has substantially the same composition as the slurry S _1, and
The last molded part of the molded body 3 has substantially the same composition as the slurry S _2, and the part formed between them has a continuously and smoothly inclined composition.

As described above, according to the method for forming a functionally gradient material of the above embodiment, the composition (mixing ratio) is not stepwise,
It is possible to surely form a functionally gradient material having a smooth gradient. Further, since the slurry S ₁ or S ₂ which is a liquid or the mixed slurry S _{1 + 2} (FIG. 3) of S ₁ and S ₂ serves as a pressure medium, the pressure applied to the entire molded body 3 becomes uniform, For example, even in the case of forming a thick molded body 3 having a thickness of 50 mm or more, the density of the inside (central portion) does not decrease, and deformation occurs in the step of firing the functionally graded material after molding. It can be prevented from occurring.

In the above embodiment, the case where two kinds of slurries S ₁ and S ₂ are used has been described, but it is also possible to form the functionally gradient material using three or more kinds of slurries. In that case, for example, if three kinds of slurries S ₁ , S ₂ , and S ₃ (not shown) are used, after the supply slurry is switched from S ₁ to S ₂ , the slurry retained in the dehydration molding container is it may be performed switching to supply the slurry S ₃ when almost fully substituted on S _2.

In the method for molding a functionally gradient material of the present invention, the timing of switching the type of slurry is not limited to the above embodiment, but the degree of inclination (inclination angle) to be imparted to the molded body. It is possible to arbitrarily determine the timing for switching the slurry in consideration of the composition and its mode, and thereby the composition inclination angle and the mode can be arbitrarily adjusted.

The method of forming a functionally graded material of the present invention is not limited to the method of forming a functionally graded ceramic material, and other inorganic materials, organic materials, or a combination of inorganic and organic materials can be used. It can be widely applied to a molding method of a functionally gradient material made of.

[0021]

As described above, according to the method for molding a functionally gradient material of the present invention, a slurry containing a raw material powder such as a ceramic raw material is supplied to a dehydration molding container, which is pressurized and dehydrated to a predetermined shape. In a series of dehydration molding steps for molding, the slurry to be supplied is switched to a different type of slurry in the middle of the dehydration molding step, and the composition of the slurry retained in the dehydration molding container is changed in time series, thereby performing dehydration molding. Since the composition of the molded body to be formed is continuously changed, it is possible to reliably form a functionally graded material having a gradually changed composition and a small gradient strain.

Further, since it is possible to mold so that the density distribution becomes uniform, it is possible to mold, for example, a thick functionally gradient material having a thickness of 50 mm or more. Further, the density of the inside (center portion) of the formed functionally gradient material does not decrease, and it is possible to prevent deformation during firing.

Further, by adjusting the timing of switching the type of slurry and the feed rate of the slurry, it is possible to arbitrarily change the mode of composition inclination and the angle of composition, and to select from three or more types. The composition can be graded by using the raw materials.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing one step of a method of manufacturing a functionally gradient material of the present invention.

FIG. 2 is a cross-sectional view showing another step of the method for producing a functionally graded material of the present invention.

FIG. 3 is a cross-sectional view showing another step of the method for producing a functionally graded material of the present invention.

FIG. 4 is a cross-sectional view showing another step of the method for producing a functionally graded material of the present invention.

FIG. 5 is a diagram schematically showing a state of particles (for example, ceramic raw material powder) in a slurry.

FIG. 6 is a diagram schematically showing a state where a molded body (cake layer) is formed in the dehydration molding container.

[Explanation of symbols]

1 Dewatering molding container filtration surface 2 Dehydration molding container 3 Molded body (gradient functional material) S ₁ Slurry of the first composition S ₂ Slurry of the second composition S _{1 + 2} S _{1 +} S ₂ mixed slurry

Claims (1)

[Claims] 1. A series of dehydration molding steps in which a slurry containing a raw material powder such as a ceramics raw material is supplied to a dehydration molding container and is dehydrated under pressure to be molded into a predetermined shape. By changing to a different type of slurry during the molding process and changing the composition of the slurry that remains in the dehydration molding container in time series, the composition of the molded body to be dehydrated and molded can be changed continuously. And a method for forming a functionally gradient material.