JP3049937B2 - Ceramic firing sagger - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic firing sagger used for firing a ceramic molded body.

[0002]

2. Description of the Related Art Conventionally, when a firing operation of a ceramic molded body used as a positive temperature coefficient thermistor element or the like is performed, a structure shown in a partially broken perspective view of FIG. It is common to use a sagger 10 (hereinafter referred to as a sagger). That is,
The sagger 10 itself is also formed using ceramics, and has a storage recess 11 for storing a large number of ceramic molded bodies S to be fired therein.

[0003] Each of the ceramic molded bodies S packed in the storage recess 11 of the sagger 10 is provided with a base plate, a roller or the like that moves in a continuous firing furnace in which the sagger 10 is called a tunnel type. While being placed and transported on a moving medium (both not shown), it is baked by being supplied with thermal energy. As shown in FIG. 9, the method for packing the ceramic molded bodies S to be fired is such that the main surface of each ceramic molded body S is perpendicular to the bottom surface 11a of the storage recess 11 ( Hereinafter, referred to as a method A) or, as shown in FIG. 10, a method of packing the ceramic molded bodies S such that the main surface thereof is horizontal with respect to the bottom surface 11 a of the storage recess 11 (hereinafter referred to as a method B).
In general, one of the following is adopted.

[0004]

Incidentally, the above-described firing operation of the ceramic molded body S is performed to adjust the resistance value of the ceramic molded body S by promoting the grain growth accompanying heating. However, when the sagger 10 having the conventional configuration is used, the following inconvenience occurs. That is, the individual storage positions of the ceramic molded bodies S in the storage recesses 11 are different from each other, and are stored in various positions such as an inner side and an outer side in the storage recesses 11. In spite of firing under the internal temperature condition, a temperature difference occurs between the ceramic molded bodies S, which causes different sintering behavior. As a result, the resistance value of each of the fired ceramic molded bodies S is reduced. It will be different and will vary greatly.

The present invention has been made in view of such a conventional inconvenience, and has been developed in view of the fact that the fired ceramic molded bodies have different resistances, despite the fact that the respective ceramic molded bodies have different storage positions within the storage recesses. The aim is to provide saggers that do not vary in value.

[0006]

According to the present invention, in order to achieve the above object, a large number of ceramic compacts to be fired are housed and placed on a moving medium moving in a continuous firing furnace. a sagger of squares shape being transported Te, together if the under side of the housing recess for accommodating the ceramic molded body is provided with a space portion having an area larger than the area of the bottom surface
Formed at least along two sides of the bottom surface
Abuts on the surface of the moving medium while securing the space
It characterized in that it is provided with a supporting portion.

[0007]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a partially cutaway perspective view showing a schematic structure of a sagger according to a first embodiment of the present invention when viewed from the front side.
1 is a perspective view showing a schematic configuration when viewed from the back side, and reference numeral 1 in these figures denotes a sagger.

The sagger 1 is a moving medium (not shown) such as a base plate or a roller that moves in a continuous firing furnace.
The plurality of stored ceramic compacts S are fired while being placed on and transported, and are formed in a square shape made of alumina ceramic or the like. Further, inside the sagger 1, there is provided a storage recess 2 having only an upper surface opened for storing a large number of ceramic molded bodies S to be fired, and a lower surface of the storage recess 2 is provided below the storage recess 2. A space 3 having an area larger than the area 2a is provided.

The space 3 is formed on the bottom 1 of the sagger 1.
The pair of legs 4 are formed along the two sides of a and supported in contact with the surface of the moving medium , that is, are secured by the supporting portions . Therefore, the storage recess 2 in the sagger 1 faces the surface of the moving medium with the space 3 provided between the bottom surface 1a and the moving medium and through which the atmosphere in the furnace can circulate. The contact area between the bottom surface 1a and the moving medium is smaller than that of the sagger 10 according to the conventional example. The ceramic laminate S in the sagger 1
As described above, either of the A method of packing the main surface of each ceramic molded body S so as to be perpendicular to the bottom surface 2a of the storage recess 2 and the B method of filling the ceramic molded body S so as to be horizontal are the same as described above. It will be selected and adopted.

By the way, the present invention is not limited to the above-described first embodiment, but is shown in FIGS. 3 and 4 showing a schematic structure when viewed from the front side and the back side. A pot 5 and a sagger 6 schematically shown in FIGS. 5 and 6 show a second embodiment and a third embodiment of the present invention, respectively. Since the overall configuration of each of the saggers 5 and 6 is basically the same as the sagger 1 described in the first embodiment,
The same or corresponding parts have the same reference characters allotted, and detailed description thereof will not be repeated. First, the sagger 5 as the second embodiment has a
a is different from the sagger 1 in that it is formed at the four corners and is secured by four legs 7 that are supported in contact with the surface of the moving medium. Needless to say, the same effect as in the above is obtained. In the sagger 6 shown as the third embodiment, the space 3
Is formed below the storage recess 2 as a so-called hollow, and since the atmosphere in the furnace can flow through the space 3, the supply of thermal energy to the ceramic molded body S also stored in the storage recess 2 is also performed. The condition becomes good. What
In the sagger 6 according to the third embodiment, the bottom
Extends along two sides and completely covers the surface of the moving medium
A hollow as the space part 3 is secured by the support part that comes into contact with
It will be .

Next, in order to confirm the effects of the saggers 1, 5, and 6 according to the first to third embodiments described above, the inventors of the present invention set the saggers 1, 5, 6 and A description will be given of a comparison experiment of a temperature difference depending on a storage position of the ceramic molded body S performed using each of the saggers 10 according to the conventional example and a result thereof.

First, BaCO ₃ , SrCO ₃ , TiO ₂ , S
iO ₂ , Y ₂ O _{3 as} a semiconducting agent, and MnCO ₃ as an additive are prepared, wet-mixed according to a predetermined mixing ratio, and calcined. Then, an appropriate organic binder is added to the obtained calcined material, and the resultant is granulated.
By molding at a pressure of 00 kg / cm ² , a large number of disc-shaped samples having a diameter of 24.5 mm and a thickness of 2.8 mm are produced.

Then, a plurality of ceramic molded bodies S manufactured as samples are prepared in accordance with the method A and the method B, while the sagger 1 according to the first embodiment and the sagger 5 according to the second embodiment are prepared in advance. The sagger 6 according to the third embodiment and the sagger 10 according to the conventional example are collectively stored in the sagger 6 respectively. In the following description, samples stored in the saggers 1, 5, and 6 according to the first to third embodiments by the method A are referred to as 1-A, 2-A, and 3-A, respectively. Are displayed as 1-B, 2-B and 3-B on the other hand, while the samples stored in the sagger 10 according to the conventional example by the method A are 4-A and On the other hand, the sample stored by the method B is displayed as 4-B. Each of the saggers 1, 5, 6, and 10 is charged and transferred into a continuous firing furnace set at a furnace temperature of 1300 ° C., so that the ceramic molded bodies S stored therein are transferred.
Is fired.

Further, samples 1-A to 4-
An In-Ga electrode is formed on each surface of A, and 25 ° C.
Resistance at R ₂₅ (Ω), with measuring the F-voltage indicating the thermal breakdown characteristics by rush current (V), the samples 1-A, the sample after having divides each ...... As shown in FIG. 7 When the specific resistance distribution, that is, the ρ variation was measured, the results shown in Table 1 were obtained. In addition, about this ρ variation, standard deviation / average value × 100 = CV%
Displayed with. In Table 1, the average value x of the crystal particle diameter in each sample obtained by the image analysis is shown.
(Μm) and standard deviation σ _n-1 (μm).

[0016]

[Table 1]

Further, according to the measurement results shown in Table 1, the first case is more than the case where the sagger 10 according to the conventional example is used.
When the ceramic molded body S is fired using each of the saggers 1, 5, and 6 according to the third embodiment, the F withstand voltage is improved by about 20% and the ρ variation is 1 / 2 or less, which indicates that the uniformity of the sample is greatly improved. It is clear that the same applies to the variation in the crystal particle diameter.

Further, Samples 1-B to
An In-Ga electrode was formed on each surface of 4-B,
The resistance value R _{25 at} 25 ° C. of each of the samples stored in the lowermost part of each of 5, 6, and 10 and other positions.
When the average value x (Ω) and the variation CV (%) were measured, the results shown in Table 2 were obtained.

[0019]

[Table 2]

According to the measurement results shown in Table 2, the average value x (Ω) of the resistance value R ₂₅ of the sample 4-B stored in the lowermost position of the sagger 10 according to the conventional example.
And the variation CV (%) are abnormally large compared to the others, whereas the saggers 1 according to the first to third embodiments
Sample 1 stored at the lowest position of each of 5 and 6
B, 2-B and 3-B do not show much difference. For the samples stored in positions other than the lowermost portions of the saggers 1, 5, 6, and 10, both the average value x (Ω) of the resistance value R ₂₅ and the variation CV (%) are similar to each other. It can be seen that there is not much difference.

[0021]

As described above, according to the sagger according to the present invention, the lower side of the storage recess for storing a large number of ceramic molded bodies to be fired has an area larger than the area of the bottom surface thereof. A space is provided and at least the bottom
While being formed along two sides of the surface,
Since it has a support part that contacts the surface of the moving medium ,
Despite the difference in the storage positions of the ceramic molded bodies in the storage recesses, there is no longer a temperature difference between the ceramic molded bodies S, and the resistance values of the fired ceramic molded bodies are different. An excellent effect is obtained that the operation is not performed.

[Brief description of the drawings]

FIG. 1 is a partially broken perspective view showing a schematic configuration of a sagger according to a first embodiment when viewed from the front side.

FIG. 2 is a perspective view showing a schematic configuration when the sagger according to the first embodiment is viewed from the back side.

FIG. 3 is a partially broken perspective view showing a schematic configuration of a sagger according to a second embodiment when viewed from the front side.

FIG. 4 is a perspective view showing a schematic configuration when the sagger according to the second embodiment is viewed from the back side.

FIG. 5 is a partially broken perspective view showing a schematic configuration of a sagger according to a third embodiment when viewed from the front side.

FIG. 6 is a perspective view showing a schematic configuration when the sagger according to the third embodiment is viewed from the back side.

FIG. 7 is an explanatory view showing a divided state of a sample.

FIG. 8 is a partially cutaway perspective view showing a schematic configuration of a sagger according to a conventional example.

FIG. 9 is an explanatory view showing a method A when packing the ceramic laminate.

FIG. 10 is an explanatory view showing a B method when packing the ceramic laminate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sagger (sinter for ceramic firing) 2 Storage recess 2a Bottom surface 3 Spatial part S Ceramic molded body

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-52-11206 (JP, A) JP-A 61-181297 (JP, U) JP-A 34-11563 (JP, Y1) JP-A 49- 41488 (JP, Y1) (58) Field surveyed (Int. Cl. ⁷ , DB name) F27D 3/12 F27B 9/00-9/40 C04B 35/64

Claims (1)

(57) [Claims] 1. A box-shaped ceramic firing sagger containing a large number of ceramic molded bodies (S) to be fired and placed and transported on a moving medium moving in a continuous firing furnace. A storage recess (2) for storing the ceramic molded body (S);
A space (3) having an area larger than the area of the bottom surface (2a) is provided on the lower side, and at least
After being formed along two sides of the bottom surface (2a),
Contacting the surface of the moving medium while securing the space (3)
A sagger for firing a ceramic, comprising a support portion (4) .