JPH0222474A - Production of ceramic material and reaction furnace for said production - Google Patents

Abstract

PURPOSE:To produce a ceramic material as a film of an extremely uniform thickness by rotating a section in a reaction furnace, introducing a reactive gas into the furnace from a direction orthogonal to the central axis of the section and exhausting the gas from the opposite side after a reaction. CONSTITUTION:A section 9 is detachably attached to the end of the rotating shaft 11 of a section rotating mechanism 10 in a reaction chamber 5 in a water- cooled chamber 1 so that the central axis of the section 9 meets at right angles to a reactive gas introducing pipe 6. A reactive gas is introduced into the chamber 5 from a direction orthogonal to the central axis of the section 9 and is exhausted from exhaust holes 8 on the opposite side. At the same time, the section 9 is rotated by the mechanism 10 and the reactive gas is allowed to react by heating with a heating element 14 in a heating chamber 12. The reactive gas is uniformly distributed on the surface of the section 9 and a ceramic material is formed on the section 9 as a film of a uniform thickness.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to SIC, S! Ceramic coatings and molded bodies such as J4, BN, etc. are hereinafter referred to as ceramic materials. ), and a method for manufacturing ceramic materials that can obtain products with stable product quality and particularly uniform ceramic film thickness at reduced costs by chemical vapor phase reaction method (hereinafter referred to as CVD method). This relates to a manufacturing reactor.

[Prior art] SIC, S! Ceramics such as 3N4, BN, etc.
It is an industrial material with excellent properties such as high melting point, inertness, high thermal stability, and high thermal conductivity, and is widely used in various fields. Such ceramics are produced using C, which uses reactive gas as a raw material.
It is widely known that it can be manufactured by the VD method. That is, for example, BN is prepared using boron halide gas and ammonia gas as reaction gases at a reaction temperature of 1450 to
It can be produced by reacting at 2300° C. and a pressure of 1 to 5 Orr.

However, when such ceramics are usually manufactured by the CVD method, an apparatus is used in which a vacuum reaction chamber heated by a heating element is installed in the chamber, a mold is placed in the reaction chamber, and the mold is heated to a predetermined temperature. Either by introducing a reactive gas using a nozzle or the like in a heated state and depositing ceramics on the mold material under a predetermined pressure to form the desired coating, or by peeling the ceramics deposited on the mold material from the mold material. A ceramic material is obtained as a molded body, and at this time, a high frequency heating method or a resistance heating method is adopted as a means for heating the mold material. That is, conventionally, as shown in FIG. 2, a resistance heating type reaction furnace includes a heating body 14 installed in a vacuum chamber 1, a reaction chamber 5,
A reaction gas is introduced into a reaction system consisting of a mold material 9 fixed in a reaction chamber 5 using a reaction gas introduction pipe 6, and ceramics are deposited on the heated mold material 9.

[Problem to be solved by the invention] Generally, the thickness distribution of ceramics deposited on a mold material is as follows:
It is greatly influenced by the gas concentration distribution on the mold material and the gas flow. Generally speaking, in order to eliminate non-uniform gas flow, it is sufficient to determine the pressure and flow conditions that will result in a laminar flow in each reactor, but on the other hand, the uniformity of the concentration of reactant gas on the mold material , it largely depends on the structure inside the furnace, such as the method of installing the mold material in relation to the reaction gas. For this reason, it is necessary to optimize these conditions in order to deposit ceramics with a uniform thickness on the mold material. However, when manufacturing large-sized ceramic materials such as ceramic crystal growth crucibles and rocket nozzles using the CVD method, it has been difficult to make the gas concentration and gas flow uniform over the entire surface of the large-sized shape. This is difficult with a reactor like the one mentioned above. That is, in the conventional reactor, from the lower end e to the upper end f of the reaction gas profile.
As the reaction progresses and the concentration of the reaction gas decreases as ceramics are deposited on the mold material, the gas concentration at the upper end f of the mold material is essentially lower than the gas concentration at the lower end e. Therefore, there was a problem in that the thickness of the ceramic film deposited on the mold material was non-uniform between e and f.

When ceramic materials are actually produced by the CVD method, the reaction is often carried out under conditions where a supply law reaction occurs, so the non-uniformity of the reaction gas concentration on the mold material is directly caused by
This was a major cause of uneven thickness of the ceramic film deposited on the mold material.

For this reason, in the past, when manufacturing ceramic materials, especially molded bodies, it was necessary to make the film thickness uniform by cutting, etc. after peeling from the mold material, which caused the problem of increasing the manufacturing cost of the product. .

The present invention solves the above problems and makes it possible to make the reaction gas concentration on the mold material uniform when manufacturing large-sized ceramic materials such as crystal growth crucibles by the CV[) method, and to achieve a uniform film thickness distribution. The purpose is to obtain a means to manufacture products that have the following characteristics.

[Means for Solving the Problems] In order to solve the above-mentioned problems and achieve the above-mentioned objects, the present inventors have conducted intensive research on methods of introducing reaction gases and manufacturing of reaction chambers. He discovered that the objective could be achieved by installing a mold material attached to a mold material rotation mechanism, introducing the reactive gas in a direction perpendicular to the central axis of the mold material, and exhausting it on the side opposite to the introduction side. The invention was completed. That is, the first embodiment of the present invention is a chemical vapor phase reaction method in which a reactive gas is introduced and a ceramic material is produced on a mold material at high temperature. The second embodiment is a method for manufacturing a ceramic material in which a reaction gas is introduced in a direction perpendicular to the direction and discharged from the side opposite to the introduction side to cause a reaction. In a phase reaction processing furnace, there is a chamber in which cold water is passed through a double wall to provide cooling ability, a reaction chamber fixedly installed in the chamber, a mold rotation mechanism that rotates a mold installed in the reaction chamber, and a reaction chamber. A heating chamber provided between the chambers and having a heating element therein, a reaction gas introduction pipe capable of introducing a reaction gas into the reaction chamber from the outside of the chamber in a direction perpendicular to the central axis of the mold material, and the reaction gas introduction tube. This is a reactor for producing ceramic materials, consisting of a pipe and an exhaust pipe connection provided on the opposite side.

Next, the present invention will be described in detail based on the accompanying drawings.

FIG. 1 is a side sectional view showing one embodiment of the reactor of the present invention.

Reference numeral 1 denotes a chamber, which has a cylindrical shape made of, for example, SUS, has a double-walled outer wall, and is provided with a cooling port 2 and a cold water outlet 3 so that cold water can be passed through the chamber to provide cooling performance. Since the reaction in the CVD method is processed at a high temperature of 1450°C or higher, heat radiation to the outside of the chamber 1 can be alleviated.
- It is made airtight and removable via the ring 4.

Reference numeral 5 denotes a reaction chamber, which is made of, for example, graphite and formed into a box shape. 2 is provided with an exhaust hole 8.

Reference numeral 9 denotes a shape material, which is detachably attached to the end of the rotating shaft 11 of a shape material rotation mechanism 10 of an appropriate mechanism attached to the chamber 1 so that the central axis of the shape material 9 is perpendicular to the reaction gas introduction pipe 6. , and its surroundings can be filled with the reaction gas and reaction product gas introduced from the reaction gas introduction pipe 6. A heating chamber 12 is provided between the reaction chamber 5 and the chamber 1, partitioned by a partition wall 13 made of a heat insulating material, and a heating element 14 made of, for example, graphite is installed inside. Reference numeral 15 denotes an exhaust pipe connection section, which is provided on the opposite side from the reaction gas introduction pipe 6, and is connected to an exhaust fan (not shown).
An exhaust pipe is connected to the exhaust pipe.

The production of the ceramic material in the present invention is carried out using the reaction furnace configured as described above, and the mold material 9
Installation, heating, and other manufacturing conditions may be carried out according to conventional conditions, but in the present invention, the mold material rotation mechanism 1
A reaction gas is introduced into the reaction chamber 5 from a direction perpendicular to the central axis of the mold material 9 attached to the end of the rotary shaft 11 of the mold material 9, and the mold material 9 is rotated at a rotational speed of several revolutions per minute (1 There is no big difference whether it is 3 revolutions per minute or 3 revolutions per minute.
The exhaust gas is introduced into the reaction chamber 5 perpendicularly to the central axis of the mold material 9, distributed uniformly on the surface of the mold material 9, and reacted on the mold material 9. After that, the exhaust gas passes through the exhaust hole 8 and exits to the exhaust pipe connection part 15. is discharged from. As a result, the concentration of the reaction gas reaching the surface of the mold material 9 from the lower end e to the upper end f of the mold material 9 becomes equal, and the film thickness of the ceramic material from the lower end e to the upper end f of the mold material 9 changes due to the rotation effect of the mold material 9. Coupled with this, uniform precipitation can be achieved. Therefore, according to the present invention, it is possible to avoid the non-uniform concentration of the reactive gas on the mold material as in the prior art, and thus it is possible to produce a ceramic material with extremely good film thickness uniformity.

[Example] Next, examples of the present invention will be described.

Example A chamber made of SUS with an inner diameter of 850 mm and a length of 1300 mm that allows cold water to pass through the double outer wall layer, and a width of 300 nm.
A graphite reaction chamber with a length of 400 ITlIT+ and a height of 300 mm was installed, a graphite heating chamber with a graphite heating element was installed, and a reaction gas produced by connecting SUS and graphite. A reactor equipped with an inlet pipe is used, and a diameter of 100 m is placed in the center of the reaction chamber.
A rectangular shape made of graphite with a height of 100 mm was attached to the end of the rotating shaft of the shape rotation mechanism, and BCρ31005CCH, NH35753CC)1 was introduced as a reaction gas into the reaction chamber through the reaction gas introduction pipe so as to be perpendicular to the central axis of the shape. , 8N was generated on the mold material by reacting for 5 hours at a temperature of 1800° C., a pressure of 1'rorr, and a rotation speed of the mold material of 1 r, l), m.

For the produced [3N product, the film thickness was measured from the lower end e to the upper end f to determine the film thickness distribution. The results are shown in Figure 3.

As a result, it was confirmed that the present invention can produce a ceramic material with excellent film thickness uniformity.

Comparative Example Using a conventional reactor of approximately the same size except for the mold material rotation mechanism in the example, BN was produced under the same conditions as in the example except that the mold material was not rotated, and in the same manner as in the example. The film thickness distribution was measured. The results are shown in Figure 4.

[Effects of the Invention] The present invention enables the mold material attached to the reaction chamber to be rotated, introduces the reaction gas in a direction perpendicular to the central axis of the mold material, and discharges it to the side opposite to the introduction side. Since this is a manufacturing method using a reactor, it is possible to manufacture ceramic materials with superior film thickness uniformity compared to conventional manufacturing methods using a conventional reactor, and cutting processes etc. are required to make the film thickness uniform. Not only does this eliminate the need for large-sized, thick-film ceramic materials, but when the total amount of precipitation is determined by the amount of reactant gas supplied, it reduces the amount of precipitation in unnecessary areas. Therefore, it has been recognized that it has extremely excellent effects, such as shortening the time it takes to complete a product and lowering manufacturing costs.

[Brief explanation of the drawing]

Fig. 1 is a side sectional view showing an embodiment of the reactor of the present invention, Fig. 2 is a longitudinal sectional view showing an example of a conventional reactor, and Fig. 3 is a film thickness of 8N produced by the method of the present invention. A diagram showing an example of the distribution with the distance from the upper end f of the mold material on the horizontal axis and the film thickness (mm) on the vertical axis. 4 is a diagram showing the film thickness distribution of BN similarly to FIG. 3. FIG.

Claims (2)

[Claims] (1) In the chemical vapor phase reaction method in which a reactive gas is introduced and a ceramic material is generated on a mold material at high temperature, the reactive gas is introduced in a direction perpendicular to the central axis of the mold material while rotating the mold material in a reaction furnace. A method for producing a ceramic material, characterized in that the reaction is carried out by discharging the material from the opposite side. (2) In a chemical vapor phase reaction processing furnace that introduces a reactive gas and generates a ceramic material on a mold material at high temperature, there is a chamber in which cold water is passed through a double wall to provide cooling ability, and a chamber that is fixedly installed within the chamber. a reaction chamber, a mold rotation mechanism that rotates the mold material installed in the reaction chamber, a heating chamber provided between the reaction chambers and a heating element inside, and a reaction gas supplied to the reaction chamber from the outside of the chamber to rotate the mold material. 1. A reactor for producing ceramic materials, comprising a reaction gas introduction pipe that can be introduced in a direction perpendicular to a central axis, and an exhaust pipe connection section provided on the opposite side of the reaction gas introduction pipe.