JPS6025391B2 - Method for manufacturing ceramic sheet sintered body - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a ceramic sheet composite body, and in particular, it is an object of the present invention to provide a method that can stably and easily manufacture a smooth, high-density ceramic sheet sintered body. be.

Recently, in the field of electronic components, applied products using ceramic sheets have been actively developed and put into practical use.

Under these circumstances, there is an increasing demand for improving the precision of ceramic sheets. Expectations for cost reduction are also increasing. Conventionally, electrically insulating materials such as alumina porcelain and zirconia porcelain and piezoelectric conductive plate elements such as ceramic resonators, ceramic filters, and speakers/dimorphs are produced by cutting competitive bodies or single crystals into predetermined shapes depending on the application. It was obtained by subjecting it to a polishing process. However, this method has problems such as deterioration of electrical characteristics due to processing distortion and high processing costs that hinder mass production. Although the production of sheet-shaped ceramic compacts has been considered and some efforts have been made, the reality is that the smoothness is not sufficient and dimensional accuracy must be improved by polishing. In particular, in the case of lead-containing piezoelectric sheet compacts, warping occurs due to magnetization of the bell during brazing and shrinkage of the sheet, resulting in many products that cannot be polished, resulting in lower yields and easier processing. Could not be manufactured.
Therefore, improvements have been made to reduce warping by applying an appropriate load on the raw sheet during pod filling in the firing process, or by placing the raw sheet in an appropriate gap and firing. However, no matter which method is used, the sheet crystals are highly warped, unable to meet strict dimensional accuracy, and the polishing process cannot be removed, making these methods difficult to mass-produce. . The present invention solves these problems, and has realized a method that can easily and stably improve the smoothness of ceramic sheet sintered bodies, and at the same time can be mass-produced, has a high yield, and can be manufactured at low cost. It is something. That is, a predetermined amount of organic components such as a binder, a plasticizer, and a solvent are added to raw materials such as lead-based dielectric ceramics, alumina, zirconia, or ferrite and mixed to form a bran.

0.05~ by the Dr.Frede method using this muddy acid.
After producing a raw sheet with a certain thickness depending on the purpose within the range of 2.0 skin thickness and punching it into an arbitrary shape, powder of a high melting point oxide (for example, zirconium oxide, magnesium oxide, aluminum oxide) is added. Apply it evenly to the raw sheet. A plurality of these sheets are stacked one on top of the other and placed on a smooth floor plate made of a material with low reactivity. If the raw sheet material contains lead or other elements that evaporate at high temperatures, place it in an electric furnace with a crucible over it, decompose the resin contained in the raw sheet at a predetermined temperature, and then heat it to a predetermined temperature. Fire it with Of course, there is no need to cover the crucible when there is no risk of evaporation. In this firing, in order to mass-produce sheet carcass feeders, it is preferable in terms of cost to stack as many raw sheets as possible. When raw sheets were stacked and fired, it was observed that the lower sheet sintered body warped more than the upper sheet sintered body, and the amount was smaller.

The reason for this is thought to be that the lower the raw sheet is due to its own weight, the more the amount of warping is suppressed due to the total weight from the top. However, the sheet compacts obtained by this firing method have a large variation in the amount of warpage and have a low yield. The inventor noticed that the amount of warping was small at the bottom of the stacked sintered sheets, and determined that the amount of warping could be suppressed by the load, so he stacked a certain number of raw sheets, and then placed a sheet made of the same material as the bottom plate on top of it. The experiment was repeated by placing a board on top of the material and firing it while applying a load.

As a result, when a load was applied to the stacked sheet material to prevent warping, no warpage occurred, but poor fusion occurred in the lower layer of the stacked sheet material. These results revealed the following. In other words, in a method in which the load applied to the stacked sheets is kept constant during the process from the beginning of filling to setting, warping and failure of fusion will inevitably occur. Rather than sintering stacked raw sheets under a constant load, the present invention actively utilizes sheet contraction during the scale-silk reaction process to adjust the shrinkage rate and sheet strength at each temperature. By using a porcelain container for rice bran formation, a suitable load can be set in advance and the load can be automatically selected according to the shrinkage of the sheet during the firing process.
It is designed to eliminate warping, rutting, cracking, etc. in the fired sheet body.

Hereinafter, the method according to the present invention will be explained by giving examples.

[Example 1] First, 0.992[Pb(Mg,/3NQ/3)o. Side TiM57Zro. 03] A calcined powder having a composition of about 10.00 o0 was prepared by a known method.

To this calcined powder, 0.5 to 1.0% polyvinyl butyral is added as a binder. In addition, 3% by weight is added to the calcined powder.
Methyl alcohol of 0-6% by weight was added and mixed using a ball mill for 16-24 hours to make mudfish. This mudfish was poured onto a polyester film, formed into a sheet using a doctor blade method, and then air-dried to produce a green sheet. The raw sheet obtained as described above,
Using a punching machine, it was punched out into a disc shape with a diameter of 3Q and a thickness of 0.5 ribs.

After attaching zirconium oxide powder to the surface of the disc-shaped green sheet, as shown in Fig. 1a, place a horizontal wheel (4) on a firing base plate 3, and place it in a cylindrical porcelain firing container 2. Surrounded by The firing porcelain container 2 is structured in stages such that the diameter increases toward the top of the inner wall surface. In the figure, numeral 1 indicates stacked disc-shaped raw sheets. On the raw sheet 1, there are three load-bearing porcelain plates 4a, 4b, with different diameters.
4c is placed. The diameter of the load porcelain plate 4a is 70
It has a thickness of 3 ribs and a weight of 350 g, and is selected so that it can be locked only at the stepped portion 5 of the inner wall surface of the porcelain container 2 for firing. In addition, the load porcelain plate 4b has a diameter of 6 mm and a thickness of 2 willow.
The respective diameters were selected so that it weighs 170 g and is locked only at the inner wall step 6, and the container 4c has a diameter of 50 mm, a thickness of 2 sails, and a weight of 14 mm, and is locked at the container top section 7. ing. The total height of the firing porcelain container 2 is 4W ribs, the height of the inner wall stepped portion 5 and the inner wall stepped portion 6 is three ribs, and the height of the inner wall stepped portion 6 and the inner wall stepped portion 7 is 4W. Saha 3 willow, inner wall step 7
The height of the firing base plate 3 is 34 fences. The above-mentioned structure is shown in the perspective view cut away at the - part in FIG.

Next, set it in the electric furnace with the installation as described above,
Electricity was applied to raise the temperature to 400:00 at a rate of 20,000/hour, and this temperature was maintained for 3 hours to remove the resin. Then, the temperature was raised again at a rate of 200°C/hour. Then,
At around 115,000, the raw sheet begins to shrink, and at the same time the loading porcelain plates 4a, 4b, and 4c placed above it descend, and the topmost one of them, the loading porcelain plate 4a, begins to shrink as shown in Figure 1b. Then, it was secured to the upper surface portion 5 of the porcelain container 2 for firing. As a result, the seat has two load porcelain plates 4.
Loads b and 4c are applied. When the temperature was further increased, the shrinkage of the sheet 1 progressed, and the load porcelain 4b was locked at the step 6 on the inner wall surface of the porcelain container 2 for firing. 13
At a temperature of 0000, the sheet 1 becomes as shown in FIG.
, 4c is no longer applied.

This state was maintained for 2 hours and then cooled to room temperature at a rate of 20,000/hour to complete the firing. in this way,
In the firing process, a ceramic sheet with good smoothness can be obtained by appropriately selecting the load to be applied depending on the degree of shrinkage of the sheet to be solidified.

[Example 2] In this example, the porcelain container 2 for firing is constructed by stacking three porcelain annular bodies 2a, 2b, and 2c such that the diameter increases toward the top, as shown in FIGS. 3 and 4. I am using the one that I made.

2a has an outer diameter of 10 ribs, an inner diameter of 65 ribs, a thickness of 3 ribs, 2b
2C has an outer diameter of 100 mm, an inner diameter of 55 mm, and a thickness of 3 ribs. 2c has an outer diameter of 10 mm, an inner diameter of 45 mm, and a thickness of 34 ribs.

Regarding other components, the same ones as in Example 1 were used. First, the weight ratio of PbTi03 and P3 is 468.
Pb(Ti,Zr)03 calcined powder with a composition of 54% and 0.5 to 1% of polyvinyl butyral as a binder. % by weight, and further added methyl alcohol in an amount of 30 to 6% by weight based on the false light powder, and then milled it in a ball mill to 16 to 2% by weight.
Mud* was prepared by mixing for 4 hours. This mud curd was poured onto a polyester film, formed into a sheet by a doctor blade method, and then air-dried to produce a green sheet. This raw sheet is punched and molded into a shape with a diameter of 3 m,
After punching into a disc shape with a thickness of 0.5 and adhering zirconium oxide powder to the surface of the disc-shaped raw sheet, 4 sheets were stacked. As shown in FIG. 3a, this raw sheet is placed on a baking board 3 and surrounded by a porcelain container 2 for baking. Further, on the raw sheet 1, a load porcelain plate 4a,
4b and 4c were mounted so that they could be separated. Fourth
The figure is a partially cutaway perspective view at this time. It was set in an electric furnace in the state shown in the figure, and electricity was applied to raise the temperature to 35,030 degrees Celsius at a rate of 20,000 degrees/hour. 35000
The temperature was maintained for 4 hours to remove the resin, and then the temperature was maintained for 20
When the temperature is raised at 0q0/hour, sheet 1 reaches around 1150oo.
started to shrink, and the loading porcelain plate 4a was locked to the uppermost annular body 2c of the porcelain firing container 2, as shown in FIG. 3b.

As a result, the load on the seat 1 is reduced to the load porcelain plate 4b.
, the weight is reduced to 4c. As the temperature increases further,
The shrinkage of the seat increases, and along with this, the loading porcelain plate 4b
, 4c descend, and the middle annular body 2b of the firing porcelain container 2
The load porcelain plate 4b is locked, and the load applied to the seat is reduced to only the weight of the load porcelain plate 4c. When the temperature increases further and reaches a temperature of 130,000 ℃, the loading porcelain plate 4c is locked to the lowermost annular body 2c of the firing porcelain container 2, and the load applied to the sheet is completely removed. will be removed. After holding this state for 2 hours, the temperature decrease rate is 20
The calcination was completed by cooling to room temperature at 0° C./hour. In this manner, a highly smooth ceramic sheet can be obtained by selecting an appropriate load depending on the shrinkage of the compacted sheet during the firing process. In this example, a porcelain container for firing is constructed by stacking a series of ring-shaped bodies, but by appropriately selecting and combining the dimensions of the ring-shaped bodies, various sheet compacts can be produced. .

By using the method of the present invention, the thermal expansion and contraction curves of magnetic porcelain, alumina porcelain, zirconia porcelain, etc., in addition to the piezoelectric sheets described above, during the firing process can be experimentally determined, and the shrinkage rate and sheet strength during the firing process can be determined. By matching the porcelain plate for loading and the porcelain container for firing according to the
A highly smooth ceramic sheet without fusion or cracks can be obtained.

[Brief explanation of drawings]

Figures 1a, b, and c are diagrams for explaining an embodiment of the method for manufacturing a ceramic sheet crystal body of the present invention, and Figure 2 is a partially cutaway perspective view of the configuration of Figure 1a. be. 3a, b, and c are views for explaining another embodiment, and FIG. 4 is a partially cutaway perspective view of the configuration of FIG. 3a. 1...Stacked raw sheets, 2...
- Porcelain container for firing, 2a, 2b, 2c... Porcelain ring body, 3... Bottom plate, 4a, 4b, 4c...
... Porcelain plate for loading, 5 ... Porcelain container for firing 2
Upper surface part, 6, 7... Same stage part. Figure 1 Figure 2 Figure 3 Figure 3 Figure 4

Claims (1)

[Claims] 1. A plurality of green sheets are stacked and arranged in a firing porcelain container whose inner wall surface is structured in stages, and a plurality of loading porcelain plates of different sizes are further placed on top of the raw sheets. After stacking in a reverse stepwise manner, the raw sheets are fired, and the loading porcelain plates are sequentially separated at the stage of the inner wall surface of the porcelain container for firing according to the degree of sintering shrinkage of the raw sheets during firing,
A method for producing a sintered ceramic sheet, characterized by reducing the load applied to the sheet. 2. The ceramic according to claim 1, wherein the cylindrical firing porcelain container is constructed by stacking a plurality of porcelain annular bodies of different sizes so that the inner wall surface is stepped. Method for manufacturing sheet sintered body.