JPS61274903A - Method of molding ceramic - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] "Field of Industrial Application" This invention relates to an improvement of the slurry casting method, which is known as one of the methods for forming new ceramics, and is particularly concerned with the improvement of the slurry casting method, which is known as one of the methods for forming new ceramics. The present invention relates to a method suitable for obtaining a ceramic molded article having a uniform thin-walled shape.

``Prior art'' As has been known in the past, the slurry casting method generally uses a mold made of water-absorbing material such as gypsum; When trying to obtain a molded product with a thin-walled shape, it is difficult to mold the molded product because the molded product is severely damaged during demolding, and if the molded product has a complex shape with different wall thicknesses, moisture in the slurry Differences in water absorption distribution occur, and differences in solidification rate cause changes in shrinkage rate, causing cracks due to internal stress differences, etc.
There was a problem with its moldability.

``Problems to be solved by the invention'' As described above, the use of water-absorbing material for the thin wall part in the pouring slurry method has problems such as the occurrence of cracks due to differences in mold releasability and solidification rate. There is a problem in that it is difficult to produce a molded article having a complicated shape or a shape having a thin portion.

"Means for Solving the Problems" In order to solve the above technical problems, the present invention uses non-water-absorbing material for the part of the mold corresponding to the thin-walled part, and absorbs water only at one part of the thick-walled part. It is characterized by eliminating non-uniformity in solidification by providing a water absorbing portion on one surface of the mold so that solidification occurs in different directions.

In the present invention, by applying a hydrophobic mold release agent to the part of the mold made of a non-water-absorbing material corresponding to the thin-walled part, the properties of the mold release surface are improved and the molded product is It is possible to prevent damage to the material and facilitate molding.

“Examples” The present invention will be described in more detail below based on examples.

Example 1 FIG. 1 is a schematic structural explanatory diagram showing an example of the structure of a mold according to the present invention. In the figure, 1 is a lower frame, inside of which a plaster mold 2 is housed. In this embodiment, this plaster mold 2 constitutes a water absorbing part for the slurry. 3 is a Si rubber segment divided into multiple pieces,
It is fitted into the upper frame 4 with an inverted taper so that it cannot be handled. This Si rubber segment is made by selecting Si rubber as a non-water-absorbing material and using a prototype having the shape of a well-known turbine rotor having a thin wall portion as a formwork (not shown) having the same shape as the upper frame 4. ) and poured S+ rubber into it, and after solidifying it was divided into an appropriate number of segments with a knife or the like.

Air conduction passages 5 are provided on the mating surfaces of the Si rubber segments 3.
is formed. Further, a cavity 6 is provided in the middle of this air passage, which serves as an escape for slurry contaminated with a mold release agent or the like. Note that if more slurry than usual flows out of this area when pouring slurry, it is a good idea to plug it with clay or the like. In addition, a slurry storage part 7 is attached to the upper part of the Si rubber segment to supplement the lowering valve of the liquid level that occurs when water in the slurry is absorbed into the gypsum. The plaster absorbs water and solidifies the thick wall part and the blade part (thin wall part) from below in the same way. Further, in this embodiment, it is preferable to apply a mold release agent to the inner surface of the Si rubber segment 3 in advance in order to improve the mold releasability of the thin portion.

Using the above-mentioned mold, Si 3Na was added at a weight ratio of 90% and 21
A powder containing 3% by weight of R-type coagulation solution, 7% Y203 powder, and 5% AQ, 03 added to the above mixed powder was mixed in a 721-1r ball mill, and the mixed powder was desolvated. , add 28cc of water to 100g of raw material powder,
Furthermore, after adding 1 mα of polycarboxylic acid ammonium-based peptizer to 100 g of raw material powder, 2 mα was added in a ball mill.
A slip was prepared by mixing for 4 to 48 hours. The slip was then placed in a vacuum vessel and -720mlH
! The pressure was reduced to J to remove air bubbles in the slip, and the slip was poured into a mold made of the aforementioned 81 rubber and plaster. The cast slip absorbed water from the plaster surface at the bottom and solidified. In this state, the mold was left for 24 days until the whole solidified, and then the mold was released from the plaster surface, and the Si rubber segment was removed. After the obtained molded body was air-dried indoors, it was held in an atmosphere sintering furnace at 1800'Cx 5 hours to obtain a sintered body.

Embodiment 2 FIG. 2 shows another embodiment of the present invention, and is a schematic diagram illustrating the construction of a mold in which aluminum is selected as the non-water absorbing material.

In this embodiment, as a method of fixing the divided aluminum segments 3', a slider 8 attached to the lower part of the segment fits into a groove provided radially on the lower frame 1', and slides inside the groove. The segment was moved in the circumferential direction. For positioning, the upper frame 4' was fitted and fixed in the same manner as in Example 1. Further, as a water absorption part, a concave mold 2- was made in advance from plaster and housed in a plaster case 9 provided inside the lower frame 1-. The aluminum segment is fixed, a split ring 10 is placed on it, and a slurry storage part 7- for replenishing the amount lost when the slurry solidifies is placed. In this embodiment, the reason why the split ring is included is that this part is a machining allowance for cutting the pressed slurry part, and by providing a convex part on the inner surface, it is made easier to break due to the cutting effect.

Using a slip prepared in the same manner as in Example 1, it was poured into the mold made of the combination of aluminum and gypsum.

At this time, it is preferable to apply petroleum jelly to the mating surfaces of the aluminum molds in advance, as liquid may easily leak. The solidification of the slip started from the plaster surface as in Example 1, but after the slip solidified to the top, it was released from the mold. When the molded body thus obtained was sintered in the same manner as in Example 1, a sintered body with a good shape was obtained.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of a mold for slurry casting using Si rubber showing one embodiment of the present invention, and FIG. 2 is a schematic cross-sectional view of a mold using aluminum to explain another embodiment of the present invention. It is a configuration sectional view.

Claims (1)

[Claims] 1) In a method of molding a ceramic body having a thin-walled shape by a slurry casting method, the portion corresponding to the thin-walled shape is made of a non-water-absorbing material, and the water-absorbing portion of the slurry is made of a non-water-absorbing material. A method for forming ceramics by a slip casting method, which is characterized by forming using a mold provided on one side so that slurry solidifies from one direction. 2) As the non-water absorbing material, Si rubber, Al, brass,
2. The method for molding a ceramic according to claim 1, wherein at least one material selected from the group consisting of plastics and plastics is used.