JPS621351B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a method of mixing raw material powder with an organic substance, molding it into a sheet shape, and firing it.
The present invention relates to methods for manufacturing various ceramic thin plates including piezomagnetic vibrators, and in particular to improvements in sintering methods.

Conventionally, this type of ceramic thin plate has had a problem of warping that occurs during the sintering process. This warping is caused by a thin sheet containing a large amount of organic matter.
This is due to the fact that it is easily thermally deformed, so deformation has so far been suppressed by increasing the temperature at an extremely slow rate in the initial stage of the sintering process. However, this conventional method has the disadvantage that the sintering time is extremely long.

Another known method for preventing warping is to sinter a green ceramic sheet while applying a scissor load between flat plates made of a material that does not easily react with the sheet. According to this known method,
Thermal deformation of the sheet is suppressed in the initial stage of temperature rise, that is, when the sheet contains a large amount of organic binder, but once the sintering reaction stage is reached, cracks occur in the sheet due to the load. There is a tendency. Moreover, when the organic binder is decomposed, the central part of the sheet is kept in a sealed state, resulting in oxygen deficiency and partial reduction, making it difficult to obtain a uniform sintered product.

SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to provide a simple method for firing ceramic thin plates without causing warping or cracking.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a green ceramic sheet 1 to be sintered. However, it goes without saying that the shape is not limited.

FIG. 2 is a sectional view of the sheet molded body 1 set in the sagger 4, showing the state before sintering. In the figure,
2 is a rigid plate made of a substance that does not easily react with the sheet molded body 1, such as alumina, zirconia, magnesia, etc., and has a collar 2a on the outer periphery. 3
is a table having a property of large heat shrinkage, and may be, for example, one made by pressing the same raw material powder as the sheet molded body 1 at a relatively low pressure. 4 is a firing sagger made of alumina, zirconia or magnesia;
5 is a rigid body having a collar 5a and made of the same material as 2. 6 is the load.

The sheet molded bodies 1 and the rigid plates 2 are alternately stacked on a table 3, and by placing a load 6 thereon, the sheet molded bodies 1 are stacked without warping. The other rigid plates 5 are the ribs 2a of the upper and lower rigid plates.
The collars 5a are arranged so as to protrude between them without touching each other.

In this state, the whole thing is placed in a furnace and the temperature is raised to 500℃, where the organic matter begins to decompose.
Up to this point, the sheet molded body 1 is sandwiched between the rigid bodies 2 and is receiving a load, but when the load exceeds this point, the platform 3 begins to shrink, and the sheet molded body 1 and the rigid body 2 are gradually laminated. The body descends, the collar 2a of the rigid body 2 engages with the collar 5a of the rigid body 5, and the sheet molded body 1 is gradually released from the load, and the surface of the sheet molded body 1 is allowed to make sufficient contact with the atmosphere. Become,
The organic matter it contains is completely decomposed. At the stage where the temperature is further increased and a sintering reaction occurs, the sheet molded body 1 is released from the load, and sintering is performed without cracking or deforming. In addition, in a state as shown in FIG. 3 in which each rigid body 2 is engaged with each rigid body on both sides, the rigid body 2
The uppermost collar 2a ₁ of the rigid body 5 and the uppermost collar 5 of the rigid body 5
If the space below a ₁ is sealed, sintered products containing substances that easily evaporate during the sintering reaction stage, such as Mn-Zn ferrite, zinc oxide, lead zirconate, and titanium. Main ingredient is acid lead
This method is effective over a wide range of areas because it can suppress the evaporation of lead oxide, etc. in PZT-based piezoelectric ceramics.

As explained above, the present invention makes it possible to sinter a thin plate with good flatness in a relatively short time in sintering a sheet molded product, and is an extremely useful technology industrially.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a sheet molded body to be sintered according to the present invention, and FIGS. 2 and 3 are diagrams showing the state of sintering according to the present invention. The figure is a cross-sectional view showing the state during sintering (and after completion of sintering). In the figure, 1...Sheet molded body, 2...Rigid body, 2a
...Brim, 3...Heat-shrinkable stand, 4...Sagger, 5...
...Rigid body, 5a...Brim, 6...Load.

Claims (1)

[Claims] 1. On a table made of a material having a sufficiently large coefficient of thermal contraction, first rigid plates having ribs on both sides and unfired ceramic thin plates are stacked alternately, and on both sides of this laminate, between the upper and lower ribs, The second rigid plate is arranged and fixed so as to protrude from the top, and while heating the entire body and firing the unfired ceramic plate, the laminate is lowered by the contraction of the table as the temperature rises, and each first A method for sintering a thin ceramic plate, characterized in that each rigid body is supported by a second rigid body, whereby the ceramic plate is released from the load at a temperature above a certain temperature.