JP3484872B2 - Heat treatment method of ceramics and heat treatment sheath used for it - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat treatment method for ceramics and a heat treatment sheath used therefor .

[0002]

2. Description of the Related Art Ceramic electronic parts such as ceramic capacitors are usually manufactured through a process of heat treating a ceramic element under predetermined conditions.

In the conventional heat treatment (baking) process, for example,
By heating to a predetermined temperature, the organic binder added as a forming aid is burned, decomposed and removed, and then heated and heated to sinter the ceramics. In this way, the binder is removed before sintering the ceramics because the decomposed gas of the binder adversely affects the heat treatment atmosphere, and when the ceramics are immediately heated and heated to the sintering temperature, the temperature is suddenly increased. Object to be heat-treated (ceramic element) due to generation of decomposition gas
Due to damage or deformation.

By the way, when a large number of objects to be heat-treated (ceramic elements) are fired at the same time, conventionally, as shown in FIG. 4, for example, a plurality of ceramic elements 24 are formed on the side walls 22 whose upper surfaces are open and which face each other. After being housed in a box-shaped heat treatment sheath 21 in which a notch 23 for discharging the decomposed gas of the binder is formed, the heat treatment sheaths 21 are stacked in multiple stages and heated to a predetermined temperature to remove the binder, Furthermore, the temperature is raised to a temperature equal to or higher than the sintering temperature of the ceramics to sinter the ceramics.

However, in the above-mentioned conventional method, the hot air in the furnace enters the heat treatment sheath 21 through the notch 23 formed in the side wall 22, and the binder abruptly burns to generate a large amount of combustion gas. There is a problem that an object is cracked or deformed.

The present invention solves the above-mentioned problems, and a method of heat treating ceramics by which the binder can be removed without causing cracks or deformation of the ceramics and the ceramics can be heat-treated reliably. The purpose is to provide a heat treated pod used for it.

[0007]

In order to achieve the above object, the method for heat treating ceramics of the present invention (claim 1).
Is a method of heat-treating ceramics in a heat-treating pod
In order to obtain the desired air permeability by adjusting the porosity.
It is made of a given material and has a shape such that only the top surface is opened, and when a plurality of stacked layers are stacked, the opening is sealed by the bottom surface of the heat-treated sheath stacked on top.
Use multiple heat treatment pods to stack multiple heat treatment pods.
By applying heat treatment, the acid inside the heat-treated sheath is
The feature is that the heat treatment is performed while limiting the supply amount of the element .

The heat treatment sheath of the present invention (claim 2)
Is used in the method for heat treatment of ceramics according to claim 1.
A heat-treated sheath that has a porosity of 18 to 25%
Made of a flexible material, and only the top surface is open,
If several are stacked, the opening will not stack on top of it.
Has a shape that is sealed by the bottom of the heat treated sheath
It is characterized by doing.

Heat of ceramics according to the present invention (claim 1)
The treatment method is to adjust the porosity to obtain the desired breathability.
Made of a material to which is added, and only the top surface is open,
If you stack more than one, the openings will
Has a shape that is sealed by the bottom of the heat treated sheath
Heat treatment by using multiple heat treatment pods
By performing the treatment, oxygen is supplied to the inside of the heat-treated sheath.
Since we are trying to perform heat treatment while limiting the amount of supply,
For example, after placing the heat-treated object in the heat-treated sheath, stacking a plurality of heat-treated sheaths and putting them in a heat-treating furnace, and heating at a predetermined temperature to perform binder removal, the high-temperature atmosphere gas in the heat-treating furnace is heat-treated. It is possible to prevent the binder from burning rapidly by directly entering the inside, and it is possible to supply the oxygen necessary for decomposition and combustion of the binder at a moderate speed limited through the heat treatment sheath. Therefore, it becomes possible to surely decompose and remove the binder in the object to be heat treated without causing cracks or deformation in the object to be heat treated.

Further , the heat treatment sheath of the present invention (claim 2)
Is made of a material having air permeability with a porosity of 18 to 25%.
And when only the top surface is open and multiple pieces are stacked
The bottom of the heat-treated pod with the opening stacked on it
Since it has a shape that is sealed by the surface,
By using them in layers, it is possible to ensure limited and proper ventilation.
Since it is maintained, it is possible to perform the heat treatment while gradually supplying oxygen or the like to the inside. Therefore, it is particularly significant as the heat treatment sheath of the semiconductor ceramics that the heat treatment is preferably performed in a mildly oxidizing atmosphere. However, the heat treatment method and the heat treatment sheath of the ceramics of the present invention are not limited to the heat treatment of semiconductor ceramics,
It can also be used for heat treatment of other ceramics.

In producing the heat-treated sheath of the present invention, the porosity can be adjusted by adjusting the composition or particle size of the raw material for producing the heat-treated sheath, adding a gas-generating component, and adding a gas after molding. It is possible to apply various methods such as a method of increasing porosity by generating them.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The features of the present invention will be described in more detail below.

FIG. 1 is a perspective view showing a heat treatment sheath according to an embodiment of the present invention. This heat-treated sheath 1 is A
It is formed by using a high-purity Al ₂ O ₃ -based material containing 88.0 wt% of 1 ₂ O _{3 and} 12.0 wt% of SiO ₂ .
Its porosity is in the range of 18 to 25% and it has an appropriate air permeability.

As shown in FIG. 1, the heat treatment sheath 1 has a rectangular planar shape and a box shape with an open top surface. The side wall 2 is not provided with the notch 23 (FIG. 4) or the like provided in the conventional heat treatment sheath. Therefore, as shown in FIG. 2, when a plurality of heat-treated sheaths 1 are vertically stacked, the heat-treated sheath 1 having the upper opening 3 is stacked on the bottom surface 4 of the heat-treated sheath 1.
Will be sealed by.

Next, a method of heat-treating the semiconductor ceramic plate 11 (FIG. 3A) using this heat-treatment sheath 1 will be described. The semiconductor ceramic plate 11 is used for manufacturing a semiconductor ceramic capacitor.
As shown in (b), the semiconductor ceramic capacitor 14 is manufactured by disposing the electrodes 12a, 12b and the terminals 13a, 13b on both surfaces thereof.

First, a disk-shaped semiconductor ceramics plate (object to be heat treated) 11 is put into the heat treatment sheath 1, and then a plurality of heat treatment sheaths 1 are stacked on the base plate 6 as shown in FIG. A sealing lid 5 made of the same material as the heat treatment sheath 1 is applied to the upper heat treatment sheath 1. Instead of the sealing lid 5, another heat treatment sheath may be stacked on the uppermost layer to function as a sealing lid. Then, the stacked heat treatment sheaths are placed in a heat treatment furnace, heated under predetermined conditions to remove the binder, and further heated to raise the temperature to a temperature at which the semiconductor ceramics can be sintered. 11 is sintered.

After the binder was removed by the above method, the rate of occurrence of cracks and deformation was examined for the semiconductor ceramics plate 11 obtained by sintering the ceramics.
The results are shown in Table 1.

[0018]

[Table 1]

In Table 1, the samples marked with * are comparative examples outside the scope of the present invention, and others are examples within the scope of the present invention. Further, in Table 1, the crack occurrence rate shows the ratio of the number of semiconductor ceramic plates with cracks to the number of heat-treated semiconductor ceramic plates (the number of samples), and the deformation occurrence rate is the heat-treated semiconductor ceramic plate. For the number (sample number) of
The ratio of the number of semiconductor ceramic plates in which deformation has occurred is shown.

For comparison, (1) a heat treatment sheath (Sample No. 1) of a conventional structure having a notch on the side wall as shown in FIG. 4 and (2) no notch on the side wall. In terms of points, it is similar to the heat treatment sheath of the present invention, but heat treatment sheaths (Sample Nos. 2 and 5) having porosities outside the scope of the present invention were prepared, and these heat treatment sheaths (Sample Nos. 1, 2, 5) were prepared. The semiconductor ceramic plate 11 was heat-treated using the above. The results are also shown in Table 1.

From Table 1, in the case of using the conventional heat treatment sheath having notches on the side wall (1) (Sample No. 1), the ratio of cracks (crack) It can be seen that the occurrence rate) is 0.02%, and the deformation occurrence rate is 0.50%.

Further, when the heat-treated sheath of (2) having a porosity outside the range of the present invention of 16% was used (Sample No. 2), the crack occurrence rate was 0%, but the deformation occurred. The rate is as high as 2.06%. This is because the amount of oxygen required for the decomposition of the binder is insufficient, the binder contained in the semiconductor ceramics plate that is the object to be heat treated does not decompose uniformly, and the contraction rate varies between parts of the semiconductor ceramics plate during sintering. It is thought that this is due to the occurrence of.

Further, the porosity is outside the range of the present invention.
When using the heat treatment sheath in% (Sample No. 5),
Although the deformation occurrence rate is as low as 0.25%, the crack occurrence rate is 0.01%, which is not preferable. It is considered that this is because the decomposition of the binder proceeds too rapidly due to the excessive supply of oxygen.

On the other hand, when a heat treatment sheath within the scope of the present invention is used (Sample No. 3 (porosity 18%), 4
(Porosity 25%)), the crack occurrence rate was 0%, and the deformation occurrence rate was 0.52% (Sample No. 3).
It turns out that it is 0.31% (sample number 4).
This is because the high temperature atmosphere gas in the heat treatment furnace does not directly enter the heat treatment sheath, and the binder is decomposed,
It is considered that the oxygen required for combustion is supplied through the heat treatment sheath at an appropriate rate.

In the above embodiment, the heat treatment sheath made of high-purity alumina material is taken as an example.
The constituent material of the heat-treated sheath is not limited to this,
Other materials such as zirconia can also be used.

In the above embodiment, the heat treatment sheath having a rectangular planar shape has been described as an example. However, the shape of the heat treatment sheath of the present invention is not limited to this, and the planar shape may be circular or other than square. The shape may be rectangular, or may be another shape.

Furthermore, in the present invention, the pores formed in the heat-treated sheath do not necessarily have to be distributed throughout the sheath, but may be present at least on the side walls thereof.

In the above embodiment, the case where the semiconductor ceramics are heat-treated has been described as an example. However, the heat-treatment sheath of the present invention and the ceramic heat-treatment method using the same are not limited to the case where the semiconductor ceramics are heat-treated, but also the dielectric ceramics. It can be widely applied when heat-treating various ceramics such as body ceramics and piezoelectric ceramics.

The invention of the present application is not limited to the above-mentioned embodiment in other respects, and the invention is related to the kind of ceramics as the object to be heat-treated, its specific shape, structure, and the aspect of accommodation in the heat-treated sheath. It is possible to add various applications and modifications within the scope of the above.

[0030]

As described above, according to the present invention (claim 1) .
The heat treatment method for ceramics involves adjusting the porosity.
Made of a material with more specified breathability, and
Only the surface is open, and when stacking multiple
Sealed by the bottom of the heat-treated pods stacked on top
Use a heat treatment sheath that has a shape like
By stacking several pieces and performing heat treatment,
Perform heat treatment while limiting the amount of oxygen supplied to the interior
Therefore, for example, after the objects to be heat treated are put into the heat treatment sheath , they are stacked in multiple stages and placed in the heat treatment furnace, and the binder is heated to a predetermined temperature to remove the binder. It is possible to prevent the binder from burning directly into the heat-treated pod and suppress the rapid combustion of the binder, and at the same time, the oxygen required for the decomposition and combustion of the binder is restricted through the heat-treated pod that has air permeability. /> It is possible to supply at a moderate rate, and the binder in the heat-treated material is reliably decomposed and removed without causing cracks or deformation in the heat-treated material, and the ceramics are heat-treated efficiently. It will be possible.

The heat treatment sheath of the present invention (claim 2)
Is made of a material having air permeability with a porosity of 18 to 25%.
And when only the top surface is open and multiple pieces are stacked
The bottom of the heat-treated pod with the opening stacked on it
Since it has a shape that is sealed by the surface,
By using them in layers, it is possible to ensure limited and proper ventilation.
As it is retained, heat is gradually supplied while supplying oxygen etc. inside.
Since it can be treated, mild oxidation
It is preferable to perform heat treatment in a conductive atmosphere.
It is especially significant as a heat-treated pod.

[Brief description of drawings]

FIG. 1 is a perspective view showing a heat treatment sheath according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a stacked state of heat treatment sheaths according to an embodiment of the present invention.

FIG. 3 is a perspective view showing a semiconductor ceramic plate which is a target of heat treatment using the heat treatment sheath according to the embodiment of the present invention.

FIG. 4 is a perspective view showing a semiconductor ceramic capacitor using a semiconductor ceramic plate.

[Explanation of symbols]

1 heat treatment sheath 2 side walls 3 openings 4 bottom 5 Sealing lid 6 base plate 11 Semiconductor ceramics plate 12a, 12b electrodes 13a, 13b terminals

Claims (2)

(57) [Claims] 1. A method of heat- treating ceramics in a heat-treating sheath to adjust the porosity to impart predetermined air permeability.
Made of a material, and only the upper surface is open, when the stacked plurality, to have a shape as sealed by the bottom surface of the heat treatment sheath in which the opening is stacked thereon heat treatment
Using pods to stack multiple heat-treated pods and perform heat treatment
Therefore, do not limit the amount of oxygen supplied to the inside of the heat treatment sheath.
Heat treatment of ceramics characterized by heat treatment from
Way . 2. A method for heat treating ceramics according to claim 1.
Which is a heat-treated sheath used for , made of a material having air permeability of 18 to 25%,
In addition, if only the top surface is open and a plurality of layers are stacked, the above-mentioned opening
Sealed by the bottom of the heat-treated pods stacked on top of it
Heat treatment characterized by having a shape such as
Saya.