JPS6059196B2 - Method for firing porcelain molded bodies - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of packing porcelain molded bodies into a box and firing them, and in particular, a firing method suitable for firing a large number of porcelain molded bodies with large outer diameters and thin walls. There is something about it.

Porcelain is obtained by firing an unfired molded body formed into an appropriate shape.

This firing step is typically performed in the manner shown in FIG. 1 or 2. That is, as shown in FIGS. 1 and 2, a box 1 is prepared, a plurality of molded bodies 2 are packed therein, and the box is heated at 0 to 1250 to 1400°C.
．． Sintered porcelain is obtained by firing for 5 to 3 hours.

The material of the box 1 is usually selected from a material that does not react with the molded body 2, and is made of, for example, a porcelain material such as mullite, alumina, or a mixture of mullite and alumina. Porcelain used for electronic components is often prepared in the form of a plate, and therefore the molded body 2 is also in the form of a plate.

As a method for packing such a plate-shaped molded body 2 into a box 1, there is a method shown in FIG. 1 or FIG. 2. FIG. 1 shows so-called stacking, in which a plurality of plate-shaped molded bodies are stacked upward. FIG. 2 shows a case in which a plurality of molded bodies 2 are arranged in a horizontal direction and packed with each part of the molded bodies 2 in contact with the bottom of the box 1.
This is what is called horizontal alignment. Among these methods, the method shown in Fig. 2 has a high packing index of the compact 2 and is optimal in terms of mass production.However, in the case of a compact with a large outer diameter and thin wall thickness, Shrinkage may occur, and the sintered body obtained from the molded body 2 may fall down after firing. In addition to this falling phenomenon, a part of the molded body 2 is in contact with the bottom of the box 1, and even if a "warp" occurs during firing, there is no way to correct it; Since only the effect of increasing the size will work, a large "warp" will occur in the obtained sintered body. In other words, the method shown in Fig. 2 does not have any effect to prevent "warpage" and only produces the molded product 2 in an environment that allows "warpage" to occur.
Otherwise, it will not be applied to the sintered body. Therefore, not only the appearance of the obtained sintered body is poor, but also a serious problem arises in practical use. Therefore, conventionally, in the case of a molded body having a large outer diameter and a thin wall, the method shown in FIG. 1 is used. However, this so-called stacking in Figure 1 is
Compared to the horizontal packing shown in FIG. 2, the packing index is reduced by half, and the number of compacts 2 that can be packed at one time is reduced, which poses a big problem in terms of mass production. In addition, even in the case of Figure 1, there are fewer causes that actively cause 1-sho, compared to the case of Figure 2, but there is no means to proactively prevent 1-sho. It is not possible to completely prevent the occurrence of Ryo. Therefore, the main purpose of this invention is to
It is an object of the present invention to provide a method for firing such a porcelain molded body, which uses the horizontal packing with a high packing index shown in FIG.

A major feature of this invention is that a bottom plate made of an unfired molded body is laid on the bottom of the box.

Embodiments of the invention having this feature will be described in detail below with reference to the drawings.

FIG. 3 shows an embodiment of the invention.

FIG. 4 is a sectional view taken along line 1-1 in FIG. 3. As the box 1, a box similar to the conventional example shown in FIGS. 1 and 2 is used.

A bottom plate 3 is laid on the bottom of the box 1. The bottom plate 3 is prepared from an unfired molded body, and a material that does not react with the molded body 2 to be fired is selected. Preferably, the bottom plate 3
It is preferable that the composition be the same as or similar to that of the molded body 2.
Further, it is preferable to spread bedding powder 4 between the bottom plate 3 and the box 1 in order to make the bottom plate 3 slip easily on the bottom of the box 1. Further, it is preferable to spread bed powder 5 on the upper surface of the bed plate 3 as well in order to prevent a reaction between the molded body 2 and the bed plate 3. On such a floor plate 3, a plurality of plate-shaped porcelain molded bodies 2 are placed.
can be placed one on top of the other in an upright position. This is what is called horizontal alignment. A pair of blocks 6 are placed between the ends of the plurality of molded bodies 2 stacked in this manner. The material for the box 6 is selected to be the same as or similar to the material for the box 1. That is, the block 6 may be made of a material that does not react with the molded body 2. When the blocks 6 are arranged, it is preferable that the plurality of molded bodies 2 be slightly compressed. The molded body 2 is fired in the state shown in FIGS. 3 and 4.

At this time, as the molded body 2 is sintered, the molded body 2 or the sintered body shrinks, and at the same time, the bottom plate 3 holding the molded body 2 underneath also contracts. Therefore, the blocks 6 that sandwich the molded body 2 at both ends move inwardly as the bottom plate 3 contracts, and the molded body 2 remains sandwiched between the pair of blocks 6 until its sintering is completed. .
In this way, the molded body 2 or the sintered body does not fall down in response to its contraction, and is appropriately compressed by the block 6, so that the molded body 2 or the sintered body has a large outer diameter and a thin wall. It is possible to obtain a sintered body as small as 1" even if the material is packed horizontally. Also, because it is packed horizontally, the packing index is high and mass production is excellent. Specific examples will be explained below along with comparative examples. do.

``Example'' First, a barium titanate semiconductor ceramic molded body having a diameter of 24.5V and a wall thickness of 1.0 mm was prepared.

This was packed in a box 1 as shown in FIGS. 3 and 4, and fired in a batch furnace at 1350 DEG C. for 1 hour to obtain semiconductor porcelain. Three pieces of the semiconductor porcelain thus obtained were randomly sampled, and one piece of each sintered body was measured. This first test was conducted as follows. As shown in FIG. 5, the wall thicknesses at three points of the sintered body 7 are Tl, t2,
t3 is measured with a micrometer, and its average value T1=(t
Find 1+T2+T3)/3. In addition, as shown in FIG. 6, the apparent total wall thickness T of the sintered body 7 including zero warpage is
Measure 2 with a dial gauge. And the difference TS=
Define T2-T1 as 1 degree. As a result of this test, x
=0.07 order, S=0.013Tf0n. Here, X is the average value of the 0-slip JTS of n=30, and s is its standard deviation.From this, it was found that 1-slip is extremely small and the variation thereof is also small. Comparative Example 1 Semiconductor porcelain was obtained in the same manner as in the example by stacking the same molded bodies as in the example in one forged stack as shown in FIG.

Three cavities were randomly extracted from the obtained semiconductor porcelain, and zero warpage was measured in the same manner as in the example. As a result, x=0.
15wm. ．． s=0.037 It was ugly. Comparative Example 2 The same molded bodies as in the example were packed horizontally as shown in FIG. 2, and semiconductor porcelain was obtained in the same manner as in the example.

3C@ of the obtained semiconductor porcelain was randomly sampled, and 1 slit was measured in the same manner as in the example. As a result, X=0
．． 357177! , s=0.015? Therefore, it could not be put to practical use. As is clear from these Examples and Comparative Examples, the method shown in Comparative Example 1 is inferior to the Examples, although the method shown in Comparative Example 1 is not so great, and furthermore, in terms of mass production, the packing index is low. There's a problem.

The method shown in Comparative Example 2 requires an extremely large amount of 7 slits and cannot be put to practical use. On the other hand, what is shown in the example is J
It has a small warpage and small variation, and is excellent in mass production. As described above, according to the present invention, since the bottom plate and the block are used, it is possible to prevent the molded body or sintered body from falling down or warping. You can get a solid body.

In addition, while maintaining the quality of such porcelain sintered bodies,
Since horizontal packing is possible, a method with excellent mass productivity can be obtained. The present invention is equally applicable to barium titanate-based dielectric porcelain, alumina porcelain, and the like, regardless of the composition thereof, as well as the barium titanate-based semiconductor porcelain shown in the above embodiments. Further, it is preferable that the bottom plate used in the present invention shrinks during firing in the same manner as the molded body.

From this point of view, the composition of the pedestal and its geometry will naturally be determined.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 each show a conventional example.

Claims (1)

[Claims] 1. A method of packing a porcelain molded body into a box and firing it,
A bottom plate made of an unfired molded body is laid on the bottom of the box, and a plurality of plate-shaped porcelain molded bodies are placed on top of each other in an upright state on the bottom plate, and the plurality of stacked porcelain molded bodies are placed on top of each other. 1. A method for firing a porcelain molded body, characterized in that firing is carried out with a pair of blocks arranged so as to sandwich the ends of the porcelain molded body. 2. The method for firing a porcelain molded body according to claim 1, wherein the bed plate has a layer of bed powder added to both sides thereof.