JPH05294740A - Firing sheet of ceramic molded body containing high vapor pressure oxide - Google Patents

Abstract

PURPOSE:To easily and efficiently obtain a fired product with an object composition by preventing volatilization of a high vapor pressure oxide, in a method in which a ceramic molded body for a product containing the high vapor pressure oxide is placed on a firing table made of a refractory, heated in a closed state and fired. CONSTITUTION:A firing sheet 1 consists of a laminated layered sheet of a high vapor pressure oxide ceramic green sheet 1A and a high melting point oxide ceramic green sheet 1B and has 50-500mum thickness. The firing atmosphere becomes the atmosphere containing the high vapor pressure oxide at a high concentration due to the high vapor pressure oxide volatizing from the high vapor pressure oxide ceramic green sheet 1A. Thus the volatization of the high vapor pressure oxide from the ceramic molded body 3 for a product is prevented and the product which has an object composition and object characteristics and also is prevented from a variation can be obtained. A reaction of the ceramic molded body 3 with the firing table 2, etc., is prevented by a high melting point oxide ceramic green sheet 1B.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet for firing a ceramic molded body containing a high vapor pressure oxide, and more particularly to a ceramic for a product containing a high vapor pressure oxide in manufacturing a chip type multilayer ceramic capacitor or the like. When the molded body is placed on a refractory firing table and fired, the firing atmosphere is suitably controlled to prevent firing loss due to volatilization of the high vapor pressure oxide contained, thereby producing a product having a desired composition. The present invention relates to a sheet for firing a ceramic molded body containing a high vapor pressure oxide that can be reliably obtained.

[0002]

2. Description of the Related Art To manufacture a monolithic ceramic capacitor, for example, an internal electrode is printed on a dielectric green sheet, punched to a predetermined size, the punched sheets are stacked, pressure-bonded, and then adjusted to the size of each chip. And disconnect.
Next, the cut raw chips are placed on a ceramic baking table and baked at a temperature of 1000 to 1400 ° C. The baked chip is provided with internal electrode connection terminal electrodes at both ends, and is further electroplated to improve solder heat resistance.

Conventionally, when firing the above-mentioned raw chips, when the raw chips contain a volatile high vapor pressure oxide, the raw chips are placed on the firing to keep the firing atmosphere uniform during firing. The table is stacked in multiple stages, placed in a ceramic bowl, and fired in a sealed state.

[0004]

However, even when firing is performed in a ceramic container in a sealed state, it is not possible to reliably prevent the vaporization of high vapor pressure oxides, and therefore, Due to the vaporization of vapor pressure oxide, a fired product having the intended composition cannot be obtained. There is unevenness in firing depending on the position in the bowl, that is, the vertical position of the firing tables stacked in multiple stages, and the composition of the obtained fired product differs. However, there are drawbacks such that it is difficult to obtain desired electrical characteristics and the product characteristics vary greatly.

The present invention solves the above-mentioned conventional problems, and when a ceramic molded body for a product containing a high vapor pressure oxide is placed on a refractory firing table and heated in a closed state to be fired. ,
An object of the present invention is to provide a sheet for firing a ceramic molded body containing a high vapor pressure oxide, which can prevent the vaporization of the high vapor pressure oxide and easily and efficiently obtain a fired product having a target composition.

[0006]

The sheet for firing a ceramic compact containing high vapor pressure oxide of the present invention is a ceramic compact for a product containing high vapor pressure oxide, which is placed on a firing table made of refractory. When placing and heating in a closed state and baking,
A sheet for laying on the ceramic molded body mounting surface of the firing table, comprising a laminated sheet of the high vapor pressure oxide ceramic green sheet and the high melting point oxide ceramic green sheet, and having a thickness Is 50-500 μm
Is characterized in that

The sheet for firing a ceramic molded body containing a high vapor pressure oxide of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows an example of firing a ceramic molded body containing a high vapor pressure oxide, using a sheet for firing a ceramic molded body containing a high vapor pressure oxide according to an embodiment of the present invention. It is the perspective view which notched.

The firing sheet 1 of this embodiment is a laminated sheet obtained by laminating a high vapor pressure oxide ceramic green sheet 1A and a high melting point oxide ceramic green sheet 1B, and has a thickness (high vapor pressure). The total thickness of the oxide ceramic green sheet 1A and the high melting point oxide ceramic green sheet 1B) is 50 to 500 μm,
The area is substantially equal to the area of the base plate 2A which is the mounting surface of the ceramic molded body 3 of the firing table 2.

As shown in the figure, such a firing sheet 1 is laid and used on the firing table 2 such that the high melting point oxide ceramic green sheet 1B side becomes the mounting surface of the ceramic molded body 3.

When firing the ceramic molded body, the firing sheet 1 is laid on the base plate 2A of the firing table 2 in this way,
A large number of ceramic molded bodies (raw chips in this embodiment) 3 for products are arranged and placed on the firing sheet 1. Then, the firing table 2 on which the ceramic molded body 3 is placed,
It is packed in a baking bowl placed on a conveyor via a base plate (not shown), and the container is transferred to a baking furnace by a conveyor after being sealed and covered with an upper lid.
Firing is performed at a temperature of 000 to 1400 ° C.

As a result, the high vapor pressure oxide contained in the high vapor pressure oxide ceramic green sheet 1A of the firing sheet 1 is vaporized during firing, and the firing atmosphere becomes a high concentration atmosphere of the high vapor pressure oxide. Therefore, volatilization of the high vapor pressure oxide from the product ceramic molded body 3 is effectively prevented.

Further, since the ceramic molded body 3 is placed via the high melting point oxide ceramic green sheet 1B and does not come into contact with the firing table 2 or the high vapor pressure oxide ceramic green sheet 1A, the reaction with these does not occur. It won't happen.

In the present invention, the high vapor pressure oxide ceramic green sheet 1A of the firing sheet 1 is made of a high vapor pressure oxide or a material containing a high vapor pressure oxide contained in the ceramic compact to be fired. Therefore, in a normal case, it is preferable to use a ceramic green sheet having the same composition as the ceramic molded body to be fired.

On the other hand, a high melting point oxide green sheet 1B.
The thermal capable of preventing reaction with the ceramic body 3 is fired and baking stand 2 or high vapor pressure oxidation products green sheet 1A, as long as it is chemically stable, usually, Al ₂ O A ceramic green sheet containing one or more of ₃ , ₃ , ZrO, and MgO as a main component is used.

The high vapor pressure oxide ceramic green sheet 1A and the high melting point oxide ceramic green sheet 1B are laminated and integrated to form a firing sheet 1.

The thickness of the high vapor pressure oxide ceramic green sheet 1A and the thickness of the high melting point oxide ceramic green sheet 1B are not particularly limited as long as sufficient strength can be secured from the viewpoint of handleability and the like. Good. Usually, the high vapor pressure oxide ceramic green sheet 1A has a thickness of 30 to 200 μm, and the high melting point oxide ceramic green sheet 1B preferably has a thickness of 50 to 300 μm, and the total thickness is 50 to 500 μm. The range is appropriately set.

The illustrated example is an example of the baking sheet of the present invention, and the present invention is not limited as long as the gist of the present invention is not exceeded.
It is not limited to the illustrated method.

In the present invention, examples of the ceramic molded body for a product containing a high vapor pressure oxide to be fired include:
Lead-based, lithium-based, etc. may be mentioned.

[0020]

When the firing sheet of the ceramic molded body containing the high vapor pressure oxide of the present invention is placed in a closed container together with the ceramic molded body containing the high vapor pressure oxide and firing is performed, the firing atmosphere is High Vapor Pressure Oxide of Firing Sheet Due to the high vapor pressure oxide volatilized from the ceramic green sheet,
The atmosphere contains a high vapor pressure oxide in a high concentration. Therefore, volatilization of the high vapor pressure oxide from the ceramic molded product is prevented, and it is possible to obtain a product having a target composition and properties and having no variation. Moreover, the high-melting-point oxide ceramic green sheet surely prevents the reaction between the ceramic molded product for production and the high-vapor-pressure oxide ceramic green sheet or the firing table, so that a better product can be obtained.

[0021]

EXAMPLES The present invention will be described more specifically with reference to Examples and Comparative Examples.

Example 1 A raw chip of a laminated ceramic capacitor made of a lead perovskite ceramic dielectric was fired by the method shown in FIG. That is, a green sheet (thickness 160 μm) containing Al ₂ O ₃ as a main component and a lead perovskite-based ceramic green sheet (thickness 200 μm) having the same composition as the above-mentioned green chip are laminated and a firing sheet (length 80 mm, Width 100 mm, thickness 250 μm),
This is a baking stand (length 90mm, width 105mm, thickness 5m
m, leg length 9 mm) was laid on a base plate, and about 700 fresh chips were placed on this baking sheet.

In this way, a plurality of baking stands on which raw chips are placed via the baking sheet, each side having a length of 140 m
It is piled up in a m bowl and heated in a firing furnace at atmospheric pressure for 110
It was calcined at 0 ° C. for 2 hours.

Comparative Example 1 Raw chips were baked in the same manner as in Example 1 except that the baking sheet was not used.

Discussion In each of Example 1 and Comparative Example 1, 1000 chips obtained by firing were sampled, and the presence or absence of color unevenness on the chip surface was observed with a microscope. As a result, in Comparative Example 1,
About 30 to 40% of the firing unevenness occurred inside and on the periphery of the firing table, but in Example 1, the firing unevenness did not occur.
In addition, when the electrical characteristics of the firing unevenness generation chip obtained in Comparative Example 1 were measured, capacity deterioration occurred. From this, it is clear that the baking sheet of the present invention is effectively functioning and that by using the baking sheet of the present invention, a product having high characteristics can be obtained with a high yield.

[0026]

As described in detail above, according to the sheet for firing a ceramic molded body containing a high vapor pressure oxide of the present invention,
When firing a ceramic compact containing high vapor pressure oxide, prevent composition change due to volatilization of high vapor pressure oxide during firing, and surely prevent reaction between the ceramic compact and the firing table. A product having a desired composition and desired high characteristics can be easily and efficiently obtained with a high yield without variation among products.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view showing a firing example of a ceramic molded body containing a high vapor pressure oxide using a firing sheet according to an embodiment of the present invention.

[Explanation of symbols]

 1 Firing Sheet 1A High Vapor Pressure Oxide Ceramic Green Sheet 1B High Melting Point Oxide Ceramic Green Sheet 2 Firing Stand 3 Ceramic Molded Body

Claims (1)

[Claims] 1. When the ceramic molded body for a product containing a high vapor pressure oxide is placed on a firing table made of refractory and heated in a closed state to be fired, the ceramic molded body of the firing table is used. A sheet for laying on a mounting surface, comprising a laminated sheet of the high vapor pressure oxide ceramic green sheet and the high melting point oxide ceramic green sheet, and having a thickness of 50 to 500 μm. A sheet for firing a ceramic molded body containing a characteristic high vapor pressure oxide.