JPH0480589A - Atmospheric baking device - Google Patents

Abstract

NEW MATERIAL:To enlarge effective furnace sizes, increase the number of articles to be baked, facilitate setting and permit the enlargement of an uniformly heated zone upon heating by a method wherein the above device is provided with the main body of a furnace, having an opening at the lower part of the same, and an elevatable furnace bottom section mounted detachably on the opening, while an atmosphere introducing tube is penetrated through the bottom to introduce atmospheric gas into a space between inner and outer fire resistant vessels from the outside of the furnace. CONSTITUTION:An inside alumina crucible 54, into which articles to be baked 60 and POZ atmospheric powder 62 are charged, is put on the upper surface of a bottom lid 56a. An upper lid 54a is put on the upper opening of the alumina crucible 54. The main body section 56 of an outside alumina crucible 56 is put on the bottom lid 56a. The chain 50 of a chain block 48 is pulled into the direction shown by a solid line arrow in a diagram whereby the furnace bottom 46 is elevated from a posi tion shown by a single dotted chain line to a predetermined position shown by a solid line to bring the furnace bottom 46 into close contact with the opening of the main body 44 of the furnace and fix it thereto. Oxygen is introduced from an external source by an atmosphere introducing tube 64 into a space between the inner and outer alumina crucibles 54, 46 and a heater 52 is excited whereby the atmospheric baking can be effected.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention uses a firing furnace to process PL in a predetermined atmosphere.
This invention relates to an improvement of an atmosphere firing apparatus for firing ceramics such as ZT.

[Prior art] In recent years, electro-optic ceramics such as PLZT (for example, (
Pbo-3t Lao-as) (Zro-ss Tie
, 3. Research and development of PLZT light valves using )○, ) have become active. One of the apparatuses for firing ceramics such as PLZT without changing the composition is an atmosphere firing apparatus for firing under a predetermined atmosphere (for example, an oxygen atmosphere or a POZ atmosphere). Known examples of such atmosphere firing apparatuses include those using an electric furnace exclusively for atmosphere firing or a tubular furnace whose interior is sealed, and those using a normal atmospheric furnace as an atmosphere firing furnace. The latter, which used an ordinary atmospheric furnace as an atmosphere firing furnace, was constructed as shown in FIGS. 3 and 4. That is, an electric furnace 12 as a firing furnace is placed on the mounting table 10 . The electric furnace 12 consists of a furnace body 14 and a front door 16 that removably closes the front opening of the furnace body 14. Inside the electric furnace 12, alumina (A1□ O
A double alumina crucible (also called sagger) 22, 24 formed by 1) is provided. Inside this inner alumina crucible 22, a POZ atmosphere powder 26 made of a mixed powder of lead oxide (PbO) and zirconia (also referred to as zirconium dioxide) (ZrO A material to be fired 30 is put therein. Then, the atmosphere introduction pipe 32 made of alumina is connected to the front door 16.
and the alumina crucible 24, and introduce oxygen (02) as an atmospheric gas from the outside between the double alumina crucibles 22 and 24 to operate the heaters 34 provided in both side walls of the furnace main body 14. By doing so, firing was performed under an oxygen atmosphere and a POZ atmosphere to obtain a fired product (for example, PLZT) with little variation in composition. At this time, the POZ atmosphere powder 26 keeps the vapor pressure of lead oxide (pbo) and zirconia (ZrO2) in the alumina crucible 22 constant, and removes lead oxide (PbO) and zirconia (ZrO2) from the object to be fired 30. It functions to prevent evaporation and suppress compositional fluctuations of the object to be fired 30 during firing.

``Problem to be solved by the invention'' However, since conventional equipment using electric furnaces exclusively for atmosphere firing is closed type, the equipment is expensive and it is difficult to make equipment with large effective furnace dimensions. However, there were problems such as a large amount of atmospheric gas being required to fill the inside of the furnace with atmospheric gas. In addition, in devices using conventional tube furnaces, there is a limit to the size of the tube made of alumina, etc., so it is difficult to create a device with a large effective furnace size.
There were problems such as a large amount of atmospheric gas being required to fill the inside of the furnace with atmospheric gas. Furthermore, in the conventional apparatus shown in FIGS. 3 and 4, the atmosphere introduction pipe 32 is connected to the front door 1.
6 and the alumina crucible 24 to guide atmospheric gas from the outside between the alumina crucibles 22 and 24, the following problems occurred. (1) Since the atmosphere introduction pipe 32 crosses the inside of the electric furnace 12, when multiple sets of alumina crucibles 22.24 are installed in the electric furnace 12, the atmosphere introduction pipe 32 is placed between each alumina crucible 22.24. 32 becomes difficult to insert, and the number of double alumina crucibles 22 and 24 installed in the electric furnace I2 is limited by the atmosphere introduction pipe 32, increasing the number of objects to be fired 30 that can be fired at the same time. I can't. (2) After inserting the atmosphere introduction pipe 32 into the corresponding through hole of the alumina crucible 24 through the corresponding through hole of the front door 16, the front door 16 must be moved to close the front opening of the furnace body 14. Therefore, alumina crucible 22
．． 24 and the atmosphere introduction pipe 32 become complicated. (3) The heater 34 is located only within both side walls of the furnace main body 14.
... is not provided, it is not possible to widen the uniform temperature region (ie soaking zone) inside the electric furnace 12 during heating.

The present invention has been developed in view of the above points, and it is possible to easily increase the effective size of the furnace, increase the number of objects to be fired at the same time, and facilitate setting. It is an object of the present invention to provide an atmosphere firing device that can widen the soaking zone during heating.

[Means for Solving the Problems] The present invention involves placing double refractory containers in a firing furnace, placing the object to be fired in the inner refractory container, and connecting an atmosphere introduction pipe between the inner and outer refractory containers. In an atmosphere firing apparatus in which atmospheric gas is introduced from the outside through It is equipped with a hearth bottom part,
The atmosphere introduction pipe is characterized in that it penetrates the bottom of the furnace and introduces atmospheric gas from the outside between the inner and outer refractory containers.

``Function'' The atmosphere introduction tube penetrates the bottom of the furnace and introduces atmospheric gas between the inner and outer refractory containers, so the atmosphere introduction tube does not cross the inside of the firing furnace, and the refractory container can be inserted into the firing furnace. An atmosphere introducing pipe can be easily inserted between the inner and outer refractory containers anywhere inside. Since the bottom of the firing furnace is designed to be able to be raised and lowered, the inner and outer refractory containers and the atmosphere introduction pipe can be set on the bottom of the furnace after lowering the bottom of the furnace below the main body of the furnace. .

"Example" Figures 1 and 2 show an example of the present invention.
In these figures, 40 is a mounting base.

An electric furnace 42 serving as a firing furnace is attached to the mounting base 40. The electric furnace 42 includes a furnace main body 44 having an opening at the bottom, and a furnace bottom 46 that detachably closes the opening of the furnace main body 44.

The furnace main body portion 44 is attached to the mounting base 40 by a general-purpose means.
The furnace bottom 46 is fixed to the top of the mounting base 40.
The structure is such that it can be raised and lowered by pulling the chain 50.50 of the chain block 48.48 attached to the chain block 48.48 in the direction of the solid line arrow and the dotted line arrow.

Heaters 52 , . . . for heating the inside of the electric furnace 42 are provided in the front, rear, left and right side walls of the furnace main body 44 . A double alumina crucible (also referred to as a sagger) 54 and 56 made of alumina (Al□03) is provided on the upper surface of the furnace bottom 46 as a refractory container. An object to be fired (for example, a PLZT element) 60 is placed on a base 58, and a PO2 atmosphere powder 62 as an atmospheric substance is placed therein. The furnace bottom 46 and the outer alumina crucible 56
An atmosphere introduction pipe 64 is provided in the bottom cover portion 56a of the crucible 56a, and the atmosphere introduction pipe 64 is configured to introduce oxygen 02 as an atmospheric gas into the space between the alumina crucibles 54 and 56 from the outside. It can be configured.

Next, the operation of the above embodiment will be explained together with the setting.

(a) Chain block 48.48 chain 50.5
0 in the direction of the dotted arrow, the furnace bottom 46 is lowered to a predetermined position, as shown by the dashed line. Then, the atmosphere introduction pipe 64 is fixed through the corresponding through hole in the furnace bottom 46 .

(b) Next, the bottom cover 56a of the outer alumina crucible 56 is placed on the upper surface of the furnace bottom 46. At this time, the atmosphere introduction pipe 64 is placed so as to pass through the corresponding through hole of the bottom cover portion 56a.

(c) Next, the inner alumina crucible 54 containing the object to be fired 60 and the POZ atmosphere powder 62 is placed in the bottom lid part 56.
Place it on top of a. An upper lid portion 54a is placed in the upper opening of this alumina crucible 54.

(d) Next, the main body 56 of the outer alumina crucible 56
b over the bottom cover portion 56a.

(e) Next, by pulling the chain 50.50 of the chain block 48.48 in the direction of the solid arrow,
The furnace bottom 46 is raised from the position shown by the dashed line to the predetermined position shown by the solid line, and the furnace bottom 46 is tightly fixed to the opening of the furnace main body 44 .

(v) Next, oxygen 02 is introduced from the outside into the space between the inner and outer alumina crucibles 54, 56 through the atmosphere introduction pipe 64, and the heaters 52, . . . are heated to perform atmosphere firing.

In the above embodiment, the object to be fired was an oxide such as a PLZT element, and the atmospheric gas was oxygen O2 correspondingly, but the present invention is not limited to this. For example, the object to be fired could be a nitride. In this case, the atmospheric gas may be nitrogen N2.

"Effects of the Invention" As described above, in the atmosphere firing apparatus according to the present invention, the atmosphere introduction tube penetrates the bottom of the furnace and introduces the atmosphere gas between the inner and outer refractory containers. The atmosphere introduction pipe can be easily inserted between the inner and outer refractory containers anywhere in the kiln without having to cross the inside of the kiln. Therefore, the number of refractory containers that can be placed in the firing furnace can be increased, and therefore the number of objects to be fired that can be fired simultaneously can be increased. Furthermore, since heating parts such as heaters can be provided in the front, rear, left, and right side walls of the firing furnace, it is possible to widen the uniform temperature region (ie, soaking zone) in the firing furnace during heating. The bottom of the firing furnace is designed to be able to be raised and lowered.

The inner and outer refractory containers and the atmosphere introduction pipe can be set on the furnace bottom after the furnace bottom is lowered below the furnace main body, making it easy to set up the refractory container and the atmosphere introduction pipe. I can do it. Furthermore, since the atmosphere gas is introduced from the outside through the atmosphere introduction pipe, a normal atmospheric furnace can be used, and the effective short dimension can be easily increased.

[Brief explanation of drawings]

1 and 2 show an embodiment of the atmosphere firing apparatus according to the present invention. FIG. 1 is a partially sectional front view, and FIG. 2 is a cross section taken along the line A-A in FIG. 1. 3 and 4 show a conventional example, in which FIG. 3 is a partially sectional front view, and FIG. 4 is a sectional view taken along the line B--B in FIG. 3. 12.42...Electric furnace (firing furnace), 14.44...
Furnace main body, 16... Front door, 22.24.54.56.
...Alumina crucible (fireproof container) (also called sagger),
26.62...PO7 atmosphere powder, 30.60...To be fired, 32.64...Atmosphere introduction tube, 46...Furnace bottom, 02...Oxygen (atmosphere gas). Applicant Fujitsu General Ltd.

Claims (2)

[Claims] (1) A double fireproof container is placed in the firing furnace, the object to be fired is placed in the inner fireproof container, and atmospheric gas is introduced from the outside through an atmosphere introduction pipe between the inner and outer fireproof containers. In the atmosphere firing apparatus, the firing furnace includes a furnace main body having an opening at the lower part, and a furnace bottom that is detachably attached to the opening of the furnace main body and can be raised and lowered, and An atmosphere firing apparatus characterized in that an introduction pipe penetrates the bottom of the furnace and introduces atmospheric gas from the outside between the inner and outer refractory containers. (2) The atmosphere firing apparatus according to claim (1), wherein the refractory container is an alumina crucible, and the atmospheric gas is oxygen.