JP2595176B2 - Beta alumina tube firing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for firing a beta alumina tube in a sodium-sulfur battery.

[0002]

2. Description of the Related Art Generally, when firing a molded product of a beta alumina tube, the molded product shrinks by about 20%.
We needed to support that shrinkage.

For this reason, in the conventional sintering method, a green alumina setter and a green setter made of a green body are used, and the green setter is placed on the calcined setter, and the green molded setter is placed on the green setter. Was set to Then, firing was performed while the molded article was covered with a firing container or the like.

[0004]

However, in this conventional sintering method, the raw setter and the molded product react during the sintering process because the raw setter is made of a co-base with the molded product of the beta alumina tube. To join. For this reason, it is necessary to separate the two after firing, and there is a problem that the operation is very troublesome.

Further, in this conventional method, the green setter and the molded article are reactively joined in the firing process, so that the contraction of the raw setter is not uniform, and the resistance at the contact surface between the green setter and the baking table, etc. However, there is a problem that the roundness of the beta alumina tube is poor.

Further, in this conventional method, since the green setter of the green body is formed by using a mold, the firing is generated due to the inherent molding distortion based on the density difference, and the roundness of the beta alumina tube is reduced. There is a problem that defects are more easily induced.

The present invention has been made in view of the problems existing in such prior art, and has as its object to perform a troublesome operation of separating a beta alumina tube from a setter after firing. it is not necessary to perform, it is possible to make the efficiency up work, the roundness of the beta alumina tube can be below 0.6%, based
Appropriate joining of other parts to the outer peripheral surface of the opening of the Ta alumina tube
It is to provide a method for firing the beta alumina tube which is Ru can be performed.

[0008]

In order to achieve the above object, the invention according to claim 1 uses a setter made of spinel having a high content of magnesium oxide , and supports the molded article of the setter. Form multiple radial grooves on the surface,
Set the molded article of the beta alumina tube thereon, and firing the molded article in this state, the roundness of the beta alumina tube
It is characterized by being 0.6% or less .

The invention according to claim 2 is characterized in that the setter is a baking setter .

According to a third aspect of the present invention, the setter of the first aspect is a raw setter.

[0011]

In the method of firing a beta-alumina tube configured as described above, a setter made of spinel having a high content of magnesium oxide is used to support the molded product.
A plurality of radial grooves are formed on the surface, and a beta alumina tube molded product is set on the setter. In this state, the molded article is covered with a baking container or the like and baking is performed. In this firing process, since the setter is made of a spinel containing a large amount of magnesium oxide instead of the molded article and the co-base, the setter and the molded article do not react and join.

Therefore, it is not necessary to separate the beta-alumina tube from the setter after firing, and the work efficiency can be improved. In addition, the setter does not
In addition, multiple radial
Since the grooves were formed, heated air inside the beta alumina tube
Flow radially through each of the grooves,
Pressure and temperature acting on the entire periphery of the lower end of the pipe are equalized
Therefore, it is possible to roundness obtain 0.6% or less of the beta alumina tube. For this reason, outside the opening of the beta alumina tube
The other parts can be properly joined to the peripheral surface.

[0013]

EXAMPLES Hereinafter, the first embodiment of the method for firing the beta alumina tube embodying the invention described in claims 1 to 2,
This will be described in detail with reference to FIGS.

In the sintering method of this embodiment, a sintering setter 1 made of spinel having a high content of magnesium oxide is used, and a beta alumina tube molded article 2 is set on the sintering setter 1. Then, the firing container 3 is mounted on the firing setter 1 so as to cover the molded product 2, and these are inserted into a firing furnace (not shown) to fire the molded product 2.

The sintering setter 1 is made of MgO: Al ₂ O ₃
= 1.1 to 2.0: 1 and is formed into a substantially disk shape with spinel. And this baked setter 1
With a surface roughness (R _max ) of 20 μm or less,
0% g / cm ² , 2% deflection for 50mm span load
It is fired at 1600 ° C. so as to have the following strength characteristics.

An annular positioning projection 4 is formed on the upper surface of the baking setter 1 concentrically with the molded product 2. By engaging the outer periphery of the lower end of the molded product 2 with the positioning projection 4, the molded product 2 is formed. It can be positioned and arranged at a predetermined position on the baking setter 1. A plurality of radial grooves 5 are used in the firing setter 1.
Are formed at predetermined intervals on the upper surface of the molded article 2. The radial grooves 5 reduce the contact resistance between the sintering setter 1 and the molded article 2, and are generated on the inner peripheral side of the molded article 2 during firing through the radial grooves 5. Releases gas to the outside.

In the method of firing a beta-alumina tube of this embodiment, a sintered setter 1 made of a spinel containing a large amount of magnesium oxide is used instead of a molded body 2 of a beta-alumina tube and a co-base. The molded article 2 is fired. Therefore, in the firing process, the molded article 2 does not react with and bond to the firing setter 1.

For this reason, it is not necessary to separate the beta alumina tube from the sintering setter 1 after sintering, and the work efficiency can be improved. Further, since the molded article 2 does not react and join with the sintering setter 1, a beta alumina tube having a roundness of 0.6% or less and a predetermined value or less can be obtained. By the way, when the firing setter 1 was used and the number of the radial grooves 5 was 20, the roundness could be reduced to 0.22%.

Further, in this embodiment, since a plurality of radial grooves 5 are formed on the upper surface of the firing setter 1,
The contact resistance between the sintering setter 1 and the molded article 2 is reduced, and it is possible to prevent the molded article 2 from undergoing shrinkage distortion during the firing process. Further, the gas generated on the inner peripheral side of the molded article 2 at the time of firing is released to the outside through the radial grooves 5, so that it is possible to prevent the internal pressure of the molded article 2 from increasing and the occurrence of shrinkage distortion. In addition, since the surface of the sintering setter 1 is smooth, the molded article 2 can smoothly move on the sintering setter 1 during firing. Therefore, it is possible to reliably prevent the beta alumina tube from inducing a roundness defect. Therefore, the firing setter 1 can be repeatedly used many times.

[0020]

Second Embodiment Next, a second embodiment of a method for firing a beta alumina tube according to the first and third aspects of the present invention will be described with reference to FIG.

In the firing method of this embodiment, a raw alumina setter 6 made of spinel containing a large amount of magnesium oxide is used. Is set on the green setter 6. Then, the firing container 3 is mounted on the baking table 7 so as to cover the molded product 2, and these are inserted into a firing furnace to fire the molded product 2.

The raw setter 6 of the second embodiment is
Similar to the sintering setter 1 of the first embodiment described above, MgO:
It is formed into a substantially disk shape with spinel having a composition of Al ₂ O ₃ = 1.1 to 2.0: 1. On the upper surface of the raw setter 6, the same concentric positioning projection 8 as the molded product 2 is formed, and by engaging the inner periphery of the lower end of the molded product 2 with the positioning projection 8, the molded product 2 is removed. Raw setter 6
It can be positioned and arranged at a predetermined position above.

Now, also in the second embodiment, the raw setter 6 is not co-base with the molded product 2 of the beta alumina tube.
Made of spinel with high content of magnesium oxide. Therefore, in the firing process, the molded article 2 does not react and join to the raw setter 6. For this reason, it is not necessary to separate the beta-alumina tube from the raw setter 6 after firing, and the efficiency of the operation can be improved. Further, since the molded article 2 does not react and join with the raw setter 6, a beta alumina tube having a roundness of 0.6% or less and a predetermined value or less can be obtained.

The present invention is not limited to the configuration of the above-described embodiment. For example, the spinel composition of the setters 1 and 6, ie, the ratio of magnesium oxide to alumina, may be changed, or the positioning projections 4 may be intermittently formed. The configuration of each part may be arbitrarily changed and embodied without departing from the spirit of the present invention, such as forming or increasing or decreasing the number of radial grooves 5.

[0025]

Since the present invention is constructed as described above, it is not necessary to perform a troublesome operation of separating the beta alumina tube from the setter after firing, and it is possible to improve the operation efficiency. , Setter
Do not react with the shape and set a radial groove on the setter.
The heated air inside the beta alumina tube evenly
Due to Ukoto the roundness of the beta alumina tube 0.6%
And therefore the opening of the beta alumina tube
An excellent effect that Ru can perform other components joined to the mouth portion outer peripheral surface properly.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of a method for firing a beta-alumina tube embodying the invention described in claims 1 to 3;

FIG. 2 is a plan view showing the firing table separately.

FIG. 3 is a sectional view showing a second embodiment of a method for firing a beta-alumina tube embodying the invention described in claim 1 and claim 4;

[Explanation of symbols]

1 ... baked setter, 2 ... molded product of beta alumina tube, 5 ...
Radial groove, 6 ... raw setter.

Claims (3)

(57) [Claims] 1. Use of a setter made of spinel having a high content of magnesium oxide to form the setter .
A plurality of radial grooves are formed on the product support surface, a beta alumina tube molded product is set on it, and the molded product is fired in this state
And baking the beta-alumina tube with a roundness of 0.6% or less . 2. The method according to claim 1, wherein the setter is a sintering setter. 3. A method for firing a beta alumina tube according to claim 1, wherein said setter is a raw setter.