JPS635355B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for sintering ceramic tubular parts.

It is known that during the sintering of ceramic parts, these parts undergo shrinkage both in size and volume, and the magnitude of the shrinkage is, of course, dependent on
It is a function of sintering composition and temperature. Such shrinkage often results in large deformations of the parts.

This phenomenon is particularly noticeable in the case of tubular parts made of alkali beta alumina, which are suitable for use as solid electrolytes in sodium sulfide batteries.

Indeed, after forming into such tubular shapes, they are placed at the bottom of a sintering vessel, which is then placed in a suitable furnace to bring the parts to the sintering temperature.

It has been observed that parts sintered in this way often exhibit very large deformations, and it is therefore necessary in all cases to machine them to the desired dimensions, and also requires large amounts of material. It may even be thrown away.

Such machining operations are time consuming and expensive because many expensive diamond tools such as grinders, horns, drills, etc. must be used.

The present invention solves the above-mentioned drawbacks and provides a method suitable for sintering ceramic tubular parts without deforming the parts.The method of the present invention can easily achieve high reliability. Can be done.

Accordingly, the present invention is a method of sintering a ceramic tubular component by placing the ceramic tubular component in a container suitable for bringing the component to a sintering temperature, the method comprising: the tubular component is also provided with an extra layer on one outer wall, the tubular component is inserted into an opening made in a plate provided inside the container, and the extra layer is also supported on the edge of the opening; suspending a component within a container; inserting a solid component consisting of a body and a shoulder into the tubular component such that the shoulder is supported on the edge of the end; and sintering the container. The object of the present invention is to provide a method for sintering a ceramic tubular part, comprising the steps of: bringing the temperature to a temperature;

BRIEF DESCRIPTION OF THE DRAWINGS Other features and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, in which the following embodiments are given by way of example only and are not limiting.

Note that FIG. 1 shows an embodiment of the method according to the present invention, and FIG. 2 is a plan view of FIG. 1, with the lid of the sintering container removed.

In FIGS. 1 and 2, the entire sintering vessel is indicated at 1. This container comprises a cylindrical body 2 resting on a bottom 3, the top of which is closed with a lid 4. A shoulder 5 is provided on the inner wall of the cylindrical body 2. According to the invention, on said shoulder 5 there is a plate 6 made, for example, of sodium beta alumina.
is provided. This plate 6 has a plurality of cylindrical openings 7
are drilled, each opening having a diameter slightly larger than the outside diameter of the part 8 to be sintered, for example a tube made of sodium beta alumina and closed at the bottom. The tube is preferably closed by electrophoresis or static constant compression techniques.

The upper end of the opening of the tube 8 has a slight extension 9 on its outer wall, and the diameter of the upper end of the opening is slightly larger than the diameter of the opening 7. Furthermore, the ratio of the length to the total length of the tubular component is approximately 0.1% to 5%.
It is between % and %.

Furthermore, the block part 10, made for example of alpha alumina, comprises on the one hand a body 11, the length of which is approximately equal, and on the other hand a shoulder 12, the diameter of which is approximately equal to the diameter of the open end of the tube 8. It's summery. The tube 8 to be sintered is inserted into the opening 7 and is supported by a backing 9 which is supported on the end of said opening 7 . The tube 8 is therefore positioned suspended inside the container 1, with its closed end not in contact with the bottom 3 of the container.

Furthermore, the part 10 is supported on the open end of the tube 8 via its shoulder 12 and the body 11 of the part 10
is fitted into the pipe. Thus, during sintering the tube 8 undergoes shrinkage, but the length of the open end does not shrink due to the presence of the part 10.

When the sintering operation is completed, the tube is removed from the container 1 and the upper end of the length of the tube is cut into a tube.

The parts sintered by the method of the invention have very large regularity in dimensions, both length and diameter, excellent straightness and no unevenness of the cylindrical walls. Therefore, subsequent machining operations are easy and quick, and machining may even be unnecessary if the green parts are sized according to shrinkage during sintering.

Furthermore, the method according to the invention is simple, reliable and quick, and the loading of the parts into the sintering container can also be carried out within a short time.

Specific examples illustrating the method according to the invention are described below. The unfired part 8 has a length of 500 mm, an inner diameter of 29.2 mm, and an outer diameter of 33.8 mm. The reinforcement provided on their open ends has a length of 9 mm and a diameter of 36.4 mm.

The main body 11 of the component 10 has a diameter of 29 mm. The opening 7 in the plate 6 has a diameter of 34.5 mm. After sintering, the resulting tube has a length of 400 mm, an inner diameter of 24.7 mm, and an outer diameter of 28 mm.

The invention is preferably carried out to obtain solid electrolyte tubes made of sodium beta alumina for sodium sulfide batteries.

Of course, the invention is not limited to the embodiments described above by way of example only. In particular, minor changes may be made without departing from the scope of the invention, and certain arrangements may be changed or certain means may be replaced by equivalent means.

It is likewise clear that the claimed method is applicable to all ceramic compositions without departing from the scope of the invention.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the method according to the invention, and FIG. 2 shows a plan view of FIG. 1, with the lid of the sintering vessel removed. 1 is a sintering container, 2 is a cylindrical body, 3 is a bottom, 4 is an opening, 5 is a shoulder, 6 is a plate, 7 is a circular opening, 8 is a part to be sintered, 9 is an overlay, 10 is a solid part , 11 indicates the main body, and 12 indicates the shoulder.

Claims (1)

[Scope of Claims] 1. A method of sintering a ceramic tubular component by placing the ceramic tubular component in a container suitable for bringing the component to a sintering temperature, the method comprising: inserting the tubular component into an opening made in a plate provided inside the container and supporting the reinforcement on the edge of the opening; suspending the container in a container; inserting a solid body and shoulder part into the tubular part such that the shoulder is supported on the edge of the end; and heating the container to a sintering temperature. A method for sintering a ceramic tubular part, comprising the steps of: 2. The sintering method according to claim 1, wherein the ratio of the length of the reinforcement to the total length of the tubular component is 0.1% to 5%. 3. The sintering method according to claim 1 or 2, wherein the length of the main body of the solid part is substantially equal to the length of the reinforcement. 4 Any one of claims 1 to 3
2. The sintering method according to item 1, wherein the tubular part, the plate, and the solid part have the same ceramic composition. 5. A method according to claim 4, characterized in that the tubular part and the plate are made of alkali beta alumina.