JPH01192772A - Calcination of ceramic molded article - Google Patents

Abstract

PURPOSE:To prevent the reaction of a molded article with a molding pan during calcination and to keep the preventive effect in high workability, by covering a calcination pan made of a refractory material with a sheet composed of ZrO2 powder and an organic binder. CONSTITUTION:A calcination pan 11 made of a refractory material is covered with a sheet 12 composed of ZrO2 powder and an organic binder. A ceramic molded article 13 for ceramic capacitor, etc., is placed on the sheet and calcined. the sheet 12 can be produced either by extrusion-forming a kneaded mixture of 60-90wt.% of ZrO2 powder and 40-10wt.% of an acrylic, polypropylene or rubber binder or by dipping a base plate into a slurry containing the above components and drying the plate after extracting from the slurry. For a reaction-sensitive article, the quality of the product can be maintained more effectively by properly selecting the particle diameter of the ZrO2 powder.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for firing ceramic molded bodies such as ceramic capacitors used in various electronic circuits.

<Conventional technology> In the conventional method of firing ceramic molded bodies, Fig. 9, Fig. 1
As shown in FIG. 0, a ceramic molded body 2 constituting a ceramic capacitor or the like is placed on a firing plate 1 made of a heat-resistant material, and this is placed in a firing furnace and fired.

In addition, in order to prevent the reaction between alumina (#zOs), silica (SLOg), etc., which are the components of the firing plate 1, and Ba T=Os, Sr T=Ox, which are the components of the ceramic molded body 2, the firing plate 1 A method of applying a coating 3 made of zirconia (ZrOe) on the top as shown in FIG. 9, or a method of laying a setter 4 mainly made of ZrOr as shown in FIG. 10 is used.

<Problems to be Solved by the Invention> Among the conventional methods described above, the method of applying the coating 3 as shown in FIG.
(about 1 hour).

In other words, the thicker the coating, the shorter the life of the coating, and the thinner the coating, as shown by the arrow in Figure 11, the components migrate from the baking dish 1, and for example, in the case of capacitors, this can have negative effects on product properties such as deterioration of dielectric properties. As the number of times it is used increases, it gradually begins to contain the components of the plate 1, resulting in deterioration, a decrease in the shielding effect, and a tendency to peel.

When a setter 4 is used as shown in FIG. 10, the setter 4 increases the weight, and there are problems in terms of thermal efficiency and cracking and bending of the setter 4.

The object of the present invention is to provide a firing method that does not have the above-mentioned problems.

Means for Solving the Problems> This invention was made to solve the above problems, and consists of laying a sheet made of zirconium oxide (ZrO- powder and an organic binder) on a baking dish. The present invention provides a method of placing a ceramic molded body thereon and firing it.

<Embodiment> Next, an embodiment of the present invention will be described based on FIGS. 1 to 8.

In FIG. 1, numeral 11 is a baking dish similar to that in FIG. 9.

A sheet 12 is laid on this plate 11.

The above-mentioned sheet 12 is made of zirconium oxide (60 to 90% by weight of ZrO- powder and 40 to 10% of a synthetic resin such as acrylic or polypropylene or rubber binder) extruded into a sheet form, or A mixture of 60 to 90% by weight of zirconium powder and 40 to 10% of synthetic resin such as acrylic or polypropylene is diluted with a solvent to form a slurry, which is then molded by dipping the base plate into a slurry and pulling it up.

On the sheet 12 thus formed, a plurality of ceramic molded bodies 1 are layered with zirconium oxide powder or the like interposed therebetween.
3, and then charged into a firing furnace and fired.

The particle size of this powder is classified according to the sensitivity of the product to be baked, and the powder with a larger particle size is used for the more sensitive product.

The structure of the sheet 12 is as shown in FIG. 1, and the powder layer is uniformly dispersed. The powder layer can be made up of multiple layers of powder with small particle size as shown in Figure 2, a single layer of powder as shown in Figure 3, a single layer of powder with large particle size as shown in Figures 4 and 5, or a layer of powder with large particle size as shown in Figures 4 and 5. Although it is possible to form two layers as shown in Fig. 6, it is more effective to increase the distance between the plate 11 and the molded body 13 by controlling the particle size.

The key point of this invention is that the reactivity can be adjusted by controlling the particle size and mixing ratio of the zirconium oxide powder rather than using multiple zirconium oxide layers.

The substantial distance between the grain 11 and the molded body 13 during high-temperature reaction is determined by the particle size.

That is, the distance intersection 1 of particles with a small particle size as shown in FIG. 3 has a smaller distance history than the distance 12 of particles with a large particle size as shown in FIG.

Practically speaking, powder having a particle size of 601 to 200I is preferable.

The above-mentioned zirconium oxide sheet 12 can be used not only as a type in which zirconium oxide powder is kneaded as described above, but also as a sheet 12 made by adhering zirconium oxide powder 15 to one side of a sheet 14 formed with a binder as shown in Fig. 8. It is possible.

Since the binder of the zirconium oxide powder-containing sheet 12 is fired, the binder evaporates and only the zirconium oxide powder remains, so that the zirconium oxide powder remaining on the firing plate can be easily recovered and reused after firing.

Effects> As described above, this invention is a method in which a sheet made of zirconium oxide (ZrOt) powder and an organic binder is laid on a firing plate, a ceramic molded body is placed on top of the sheet, and then fired. It has the effects listed in.

Coating/I! It has better workability compared to the first method.
Zirconium oxide, a component of the sheet, prevents reactivity between the firing plate and the ceramic molded body.

In addition, since the sheet can be easily replaced, if the powder becomes contaminated, a new sheet can be installed, so that the reaction prevention effect does not deteriorate due to the history of use, as is the case with the coated sheet shown in FIG.

During firing, the binder is blown away and only the zirconium oxide powder is left, making it lighter than the setter shown in FIG.

For reaction-sensitive products, the quality can be maintained more effectively by appropriately selecting the particle size of the zirconium oxide powder.

When used in conjunction with a zirconium oxide coating, the life of the coating can be extended.

[Brief explanation of the drawing]

FIGS. 1 to 8 are partially cutaway enlarged longitudinal sectional views showing each embodiment of the present invention, FIGS. 9 and 10 are perspective views showing the conventional method, and FIG. 11 is an enlarged longitudinal sectional view of the method shown in FIG. 9. FIG. 11... Firing plate 12... Zirconium oxide powder sheet 13
... Ceramic molded body No. 1 Figure 5 + 1 Figure 2 Figure 6 Figure 8 Figure 7 Figure 4

Claims (1)

[Claims] In a method in which a ceramic molded body is placed on a firing plate made of a heat-resistant material and fired, a sheet made of zirconium oxide (ZrO_2) powder and an organic binder is laid on the firing plate, and the ceramic molded body is placed on top of the sheet made of zirconium oxide (ZrO_2) powder and an organic binder. 1. A method for firing a ceramic molded body, which comprises firing a ceramic molded body by placing it thereon.