WO2013009066A2

WO2013009066A2 - Vacuum heat treatment apparatus

Info

Publication number: WO2013009066A2
Application number: PCT/KR2012/005443
Authority: WO
Inventors: Woo Young Lee; Byung Sook Kim; Jung Eun Han
Original assignee: Lg Innotek Co., Ltd.
Priority date: 2011-07-12
Filing date: 2012-07-10
Publication date: 2013-01-17
Also published as: WO2013009066A3; TWI479112B; TW201314155A; KR101854781B1; KR20130008412A

Abstract

Provided is a vacuum heat treatment apparatus having a structure which is able to improve the recovery rate of synthesized powder by optimizing a shape of a reaction container, and prevent a scattering phenomenon of the synthesized power within the reaction container, and at the same time to enhance a recovery amount of the powder in such a manner that reaction gas has vortex flow thanks to a groove of a lower part of a cover unit and is discharged to the outside through an exhaust port formed on an upper part of a crucible.

Description

VACUUM HEAT TREATMENT APPARATUS

The present invention relates to a vacuum heat treatment apparatus.

A vacuum heat treatment apparatus is an apparatus for producing a desired substance by heat-treating a raw material within a crucible, and is advantageous that heat treatment is performed in a vacuum state, so pollution from surrounding environments is not generated. In the vacuum heat treatment apparatus, a heat insulating member is disposed within a chamber maintained under vacuum, and a heater is disposed within the heat insulating member, thereby heating a raw material.

However, because during a reaction, reaction gas is not discharged through an exhaust port formed in the crucible, silicon carbide power synthesized within the crucible is scattered, thereby reducing a recovery rate.

An aspect of the present invention provides a vacuum heat treatment apparatus having a structure which is able to improve the recovery rate of synthesized powder by optimizing a shape of a reaction container, and thus preventing a scattering phenomenon of the synthesized power within the reaction container, and at the same time to enhance a recovery amount of powder in such a manner that reaction gas has vortex flow thanks to a groove of a lower part of a cover unit and is discharged to the outside through an exhaust port formed on an upper part of a crucible.

According to an aspect of the present invention, there is provided a vacuum heat treatment apparatus comprising: a chamber a reaction container disposed within the chamber and a heating member for heating the reaction container within the chamber, wherein the reaction container has a space part in an inner part thereof and includes a container unit whose one surface is opened, and a cover unit for covering the container unit, wherein a lower surface of the cover unit includes an insertion area inserted into the space part, and wherein a thickness of the insertion area satisfies a range of 1/3 to 3/5 of a depth of the container unit.

According to exemplary embodiment of the present invention, the present invention has the effect which can improve a recovery rate of the synthesized powder by optimizing the shape of the reaction container and preventing a scattering phenomenon of the synthesized powder of the reaction container.

Furthermore, it is advantageous that the reaction gas has vortex flow thanks to the groove of the lower part of the cover unit and is discharged through the exhaust port formed on the upper part of the crucible, and thus a recovery amount of the powder can be enhanced.

The accompanying drawings are included to provide a further understanding of the present invention, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present invention and, together with the description, serve to explain principles of the present invention. In the drawings:

FIG. 1 is an outline view illustrating a vacuum heat treatment apparatus according to an exemplary embodiment of the present invention.

FIG. 2 is a perspective view illustrating a reaction container of a vacuum heat treatment apparatus according to another exemplary embodiment of the present invention.

FIG. 3 is a cross-sectional view taken along line ⅢⅢof FIG. 2.

FIG. 4 illustrates a lower surface of a cover unit of FIG. 2.

FIG. 5 is a perspective view illustrating the reaction container of FIG. 2 seen from a lower part.

Exemplary embodiments according to the present invention will now be described more fully hereinafter with reference to the accompanying drawings. In the explanation with reference to the accompanying drawings, regardless of reference numerals of the drawings, like numbers refer to like elements through the specification, and repeated explanation thereon is omitted. Terms such as a first term and a second term may be used for explaining various constitutive elements, but the constitutive elements should not be limited to these terms. These terms is used only for the purpose for distinguishing a constitutive element from other constitutive element. In the drawings, the thicknesses or the sizes of each layer (film), each area, each pattern or each construct may be modified for the clarity and convenience of an explanation, and thus real sizes are not completely reflected.

Exemplary embodiments of the present invention will be hereinafter explained in detail with reference to the accompanying drawings as follows.

FIG. 1 is an outline view illustrating a vacuum heat treatment apparatus according to an exemplary embodiment of present invention.

Referring to FIG. 1, a vacuum heat treatment apparatus 100 according to the present exemplary embodiment of the invention includes a chamber 10, a heat insulation member 20 disposed within the chamber 10, a reaction container 30 disposed within the heat insulation member 20 and a heating member 40. This is explained more fully as follows.

Atmosphere gas is injected into an inner part of the chamber 10 through an atmosphere gas supplying pipe (not drawn). As for this atmosphere gas, inert gas such as argon (Ar), helium (He) and the like may be used.

The heat insulation member 20 disposed within the chamber 10 may function to insulate the reaction container 30 so as to be maintained at an appropriate temperature to a reaction. The heat insulation member 20 may include graphite so as to endure a high temperature.

Furthermore, the reaction container 30, in which a mixed raw material is filled, and by a reaction thereof a desired substance is generated, is disposed within the heat insulation member 20. The reaction container 30 may include graphite so as to endure a high temperature. Gas generated during the reaction may be discharged through an exhaust port 12 connected to the reaction container 30.

The heating member 40 for heating the reaction container 30 may be disposed between the heat insulation member 20 and the reaction container 30. The heating member 40 may supply heat to the reaction container 30 using various methods. As one example, the heating member 40 may generate heat by applying a voltage to graphite.

The vacuum heat treatment apparatus 100 may be used as a silicon carbide producing apparatus that produces silicon carbide by heating a mixed raw material including a carbon source and a silicon source as one example. However, exemplary embodiments are not limited to this.

The reaction container 30 of the vacuum heat treatment apparatus 100 is explained in detail with reference to FIG. 2 and FIG. 3.

FIG. 2 is a perspective view illustrating the reaction container 30 of the vacuum heat treatment apparatus 100 according to another exemplary embodiment of the present invention. FIG. 3 is a cross-sectional view taken along line III-III of FIG. 2.

Referring to FIG. 2 and FIG. 3, the reaction container 30 of the vacuum heat treatment apparatus 100 according to the present exemplary embodiment of the invention may have an inner space, and a bottom surface thereof may have a curved shape, in particular, a circle shape or an ellipse shape. That is, the reaction container may be implemented as a construct having a side wall (a curved surface) with a curvature in a cylindrical structure so that a shape of its horizontal cross-section becomes a circle or an ellipse.

Like this, when the bottom surface of the reaction container 30 has a circle shape, the reaction container 30 may be prevented from being damaged by uniformly spreading power. In connection to this, a case, in which the vacuum heat treatment apparatus 100 is used as a silicon carbide producing apparatus for producing silicon carbide, is explained as one example

A carbon source, a silicon source and the like are filled within the reaction container 30 illustrated in FIG. 2 and FIG. 3, and silicon carbide is generated by a reaction due to a high temperature. At this time, the reaction container 30 may be composed of graphite to endure the high temperature. By a reaction of the graphite and the silicon source of the reaction container 30, a silicon carbide layer may be formed within the reaction container 30. Then, the silicon carbide layer of two different materials may be formed in the reaction container 30 composed of the graphite. In the past, because the thermal expansion coefficient of silicon carbide was larger than that of the graphite which forms the reaction container 30, a middle part of the reaction container 30 could swell up.

However, in the present exemplary embodiment, a plane shape of the reaction container 30 may include a curved shape part so that power applied to the reaction container 30 can be minimized using directional properties between heat stresses applied to the reaction container 30. Due to this, the reaction container can be prevented from being deformed and damaged.

In the present exemplary embodiment, the reaction container 30 may have a space part in an inner part thereof and may include a container unit 32 whose one surface is opened, and a cover unit 34 for covering the container unit 32.

The container unit32 has an inner space part filled with a reaction raw-material. Furthermore, a groove 322 is formed in the container unit 32 so that gas can flow into between the cover unit 34 and the container unit 32. Thanks to this groove 322, gases which can be generated at the time of heat treatment may be discharged. The groove 322 may be formed on an upper part of a side surface of the container unit and may have an uneven shape.

Furthermore, the cover unit 34 may include a first portion 341 formed in an outside area so as to come into contact with the container unit 32 from a flat upper surface 343, and a second portion 342 formed in a center area of a lower surface of the cover unit 34 so as to correspond to the space part of the container unit 32. At this time, the second portion 342 may not come into contact with the side surface of the container unit 32 and may be spaced apart from it so as to have a predetermined distance T4.

At this time, a separation distance between the second portionand the side surface of the container unit may be configured such that a ratio of a dimension T3 of the container unit 32 and the second portion 342 may range from 1:10 to 1:13, and may have 2:25.

Furthermore, when the cover unit 34 is inserted into the container unit 32, a thickness T2 of the second portion 342 of the cover unit 34 may satisfy a range of 1/3 to 3/5 or 1/2 of a depth T1 up to a bottom surface of the container unit 32.

The second portion342 formed to be adjacent to the first portion 341 and formed in a vertical lower direction of an upper surface of the cover unit may be formed to be slanted with respect to a cover surface of the cover unit 34. Like this, by forming its side surface 343 to be slanted, destruction due to a collision of the container unit 32 and the cover unit 34 can be effectively prevented. The side surface of the second portion 342 may have various shapes, and may include a rounded part as one example.

Like this, a thickness T2 of the second portion of the cover unit 34 may be formed to be deeper than a conventional thickness to thereby reduce a space in which scattering of the reaction powder is generated, and the separation distance T4 between the second portion342 and the side surface of the container unit 32 is reduced, so a path for discharging gas to the outside is narrowed.

At this time, the second portion 342 is formed as follows, thereby inducing the discharge of gas.

A gas discharging structure of the second portion will be hereinafter explained with reference to FIG. 4 and FIG. 5.

FIG. 4 illustrates a bottom surface of the cover unit of FIG. 2, and FIG. 5 is a perspective view illustrating the reaction container of FIG. 2 seen from a lower part.

Referring to FIG. 4 and FIG. 5, the cover unit according to the present exemplary embodiment of the invention may be implemented in a structure in which an intaglio groove 345 is formed on a lower surface of the second portion 342.

The groove 345 may be formed on the entire lower surface and may be implemented in a spiral line pattern which rotates along a shape of the lower surface. As illustrated in FIG. 4, the spiral line pattern may be implemented in structures, in which the intaglio groove is formed in a spiral structure from a center part of a lower surface of an insertion area to the outside, and in which a distance between each line pattern is uniformly formed or a distance between each line pattern becomes wider toward the outside from the center part. A patch of the line pattern may achieve an effect that accelerates the formation of vortex flow.

When the spiral groove 345 like the above is formed, gas generated from a reaction causes a vortex flow phenomenon along the spiral groove 345 and flows from the center part to an outside part. Accordingly, the gas is discharged to the groove 322 formed on the side surface of the container unit 32 through the separation distance T4 formed in the outside part

Experiments for explaining the effects according to exemplary embodiments of the present invention will be hereinafter explained.

<Comparative Example 1>

SiO₂and carbon black mixed in a cylindrical graphite crucible, in which an existing diameter is 500Φ, and a height is half of the diameter, were weighed. The mixed SiO₂ and carbon black were injected into a brazier and were then heat-treated for three hours at a synthetic temperature of 1400℃~1900℃ in an inert gas (Ar) atmosphere, and thereafter a recovery amount thereof to a total injection amount of 2.5kg was 400g.

<Experimental Example 1>

In addition to the crucible of comparative example 1, SiO₂and carbon black mixed in a cover of a crucible, which was devised such that a diameter is 480Φ and a thickness ratio of a bottom of the crucible is 1:2, were weighed. The mixed SiO₂and carbon black were injected into a brazier and were then heat-treated for three hours at a synthetic temperature of 1400℃~1900℃ in an inert gas (Ar) atmosphere, and thereafter a synthesized recovery amount thereof to a total injection amount of 2.5kg was 450g.

<Experimental Example 2>

In addition to experimental example 1, SiO₂ and carbon black mixed in a crucible, in which a rate of a cover of the crucible and a side surface of the crucible is 2:25, were weighed. The mixed SiO₂and carbon black were injected into a brazier and were then heat-treated for three hours at a synthetic temperature of 1400℃~1900℃ in an inert gas (Ar) atmosphere, and thereafter a recovery amount thereof to a total injection amount of 2.5kg was 475g.

<Experimental Example 3>

In addition to experimental example 2, SiO₂and carbon black mixed in the crucible, in which a spiral groove 345 is formed on a lower part of the cover of the crucible using 3T, were weighed. T The mixed SiO₂and carbon black were injected into a brazier and were then heat-treated for three hours at a synthetic temperature of 1400℃~1900℃ in an inert gas (Ar) atmosphere, and thereafter a recovery amount thereof to a total injection amount of 2.5kg was 600g.

Results of the experiments are shown in the following table 1.

Table 1

Experiment	Recovery rate	Real recovery rate to a theoretical recovery rate of 30%
Comparative Example	16%	53.3%
Experimental Example 1	18%	60%
Experimental Example 2	19%	63.3%
Experimental Example 3	24%	80%

Referring to the table, as illustrated in FIG. 1 to FIG. 5, when controlling the separation distance T4 between the container unit 32 and the cover unit 34, and the depth ratio of the second portion 342 of the cover unit 34 and the container unit 32, and forming the spiral groove 345 on the second portion 342, it can be found that the recovery rate satisfies 80% of a theoretical recovery rate.

As previously described, in the detailed description of the invention, having described the detailed exemplary embodiments of the invention, it should be apparent that modifications and variations can be made by persons skilled without deviating from the spirit or scope of the invention. Therefore, it is to be understood that the foregoing is illustrative of the present invention and is not to be construed as limited to the specific embodiments disclosed, and that modifications to the disclosed embodiments, as well as other embodiments, are intended to be included within the scope of the appended claims and their equivalents.

Claims

A vacuum heat treatment apparatus comprising:

a chamber;

a reaction container disposed within the chamber, and including a container unit which has a space part in an inner part thereof and whose one surface is opened, and a cover unit for covering the container unit; and

a heating member for heating the reaction container within the chamber,

wherein a lower surface of the cover unit is provided with an insertion area inserted into the space part.
The apparatus of claim 1, wherein a thickness of the insertion area ranges from 1/3 to 3/5 of a depth of the container unit.
The apparatus of claim 2, wherein a side wall of the reaction container is formed of a curved surface.
The apparatus of claim 3, wherein a shape of a vertical section of the reaction container is a circle or an ellipse.
The apparatus of claim 2, wherein the cover unit comprises: a first portion which is formed in an outside area so as to come into contact with the container unit from an upper surface of the cover unit and a second portion which is adjacent to the first portion and is formed in a center area of the cover unit so as to correspond to the space part of the container unit.
The apparatus of claim 5, wherein the second portion is combined in a vertical lower direction of the upper surface of the cover unit, and is implemented in a structure in which a side surface of the second portion has a slant.
The apparatus of claim 6, wherein the side surface of the second portion is formed of a curved surface.
The apparatus of claim 5, wherein the second portion and a side surface of the container unit are combined in a structure in which they are spaced apart from each other.
The apparatus of claim 8, wherein a separation distance between the second portion and the side surface of the container unit and is configured such that a ratio of a dimension of the container unit to the separation distance ranges from 1:10 to 1:13.
The apparatus of claim 8, wherein the separation distance between the second portion and the side surface of the container unit is configured such that a ratio of a dimension of the container unit to the separation distance is in a range of 2:25.
The apparatus of claim 2, wherein the insertion area has a structure in which an intaglio groove is provided to a lower surface of the insertion area.
The apparatus of claim 11, wherein the groove is implemented on the lower surface of the insertion area in a spiral line pattern.
The apparatus of claim 12, wherein the spiral line pattern has a structure in which a distance between each line pattern becomes wider toward the outside from a center of the lower surface.
The apparatus of claim 2, wherein unevenness is formed on an upper part of the side surface of the container unit.
The apparatus of claim 13, wherein the reaction container is formed of a material including graphite.