JPH0222473A - Ceramic material manufacturing method and high temperature reactor for its manufacturing - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to SIC, S! , J4, BN, and the like (hereinafter referred to as ceramic materials) using a chemical vapor phase reaction method (hereinafter referred to as CVD method).
The present invention relates to a method for manufacturing a ceramic material, which can stabilize the quality of the product, reduce costs, and significantly reduce the degree of damage to the heating element of the high-temperature reactor, and a high-temperature reactor for producing the same.

[Prior art] SIC, S! Ceramics such as 3N4.13N are industrial materials with excellent properties such as high melting point, inertness, high thermal stability, and high thermal conductivity, and are widely used in various fields.

Such ceramics are produced by CV
It is widely known that it can be manufactured by method D. That is, for example, 8N uses boron halide gas and ammonia gas as reaction gases, and the reaction temperature is 145 to 23.
It can be produced by reacting under conditions such as 00°C and a pressure of 1 to 5 Torr.

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 specific 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.

[Problems to be Solved by the Invention] However, since the high-frequency heating method, which is one of the heating methods for CVD processing, uses induction heating,
There is a problem in that the type, size, and shape of the mold material to be used are limited.On the other hand, in the resistance heating method, the type, size, and shape of the mold material are limited by using graphite as the heating element material.
Although it can be heated without being restricted by shape, etc., when an active gas such as ammonia gas is used as the raw material reaction gas, the reaction temperature is higher than 1450°C, so it generates heat. There is a problem that the heating element itself is susceptible to corrosion damage due to reaction with the raw material reaction gas and the gas generated from the raw material reaction gas, and there is also a method of manufacturing the heating element from high melting point metals such as chromium, molybdenum, and tungsten. However, these materials have poor processability and
Since it is difficult to manufacture large-sized shapes, there is also the problem that the size and shape of mold materials that can be used in manufacturing ceramic materials by the CVD method are extremely limited.

However, due to these factors, the quality of the obtained ceramic material becomes unstable and there is also a problem that the cost becomes high.

The object of the present invention is to solve the above-mentioned problems and provide a manufacturing method capable of producing products of stable quality at low cost, and a reactor suitable for the manufacturing method.

[Means for Solving the Problems] In order to solve the above problems and achieve the above objects, the present inventors have conducted intensive research using graphite, which is said to have poor corrosion resistance against active gases at high temperatures, as a heating element. As a result of further research, it was discovered that the objective could be achieved by introducing an appropriate amount of inert gas to the surface of the graphite heating element and maintaining the internal pressure of the heating chamber slightly higher than the internal pressure of the reaction chamber, and completed the present invention. It's arrived. That is, the first aspect of the present invention
In this embodiment, an inert gas is introduced into a heating chamber in a high-temperature reactor, and the internal pressure of the heating chamber is reduced by 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 caused to react while maintaining the pressure higher than the internal pressure of a chamber.The second embodiment is a method for manufacturing a ceramic material in which a reaction gas is introduced and a ceramic material is produced on a mold material at a high temperature in a chemical vapor treatment furnace. A chamber in which cold water is passed through a heavy outer wall to provide cooling ability, a reaction chamber fixed to the chamber via a fixed member, a partition wall provided adjacent to the outer wall surface of the reaction chamber, and the partition wall. and a heating chamber provided between the heating chamber and the heating chamber, a heating element fixedly installed in the chamber via an insulating member within the heating chamber, and a gas pressure adjusted from the outside of the chamber to the heating chamber by a gas pressure regulator. This is a high-temperature reactor for producing ceramic materials, which is provided with an inert gas introduction pipe for introducing an inert gas and a reaction gas introduction pipe for introducing a reaction gas from the outside of the chamber into a reaction chamber.

Next, a configuration example of the high temperature reactor of the present invention will be explained based on the attached drawings.

FIG. 1 is a longitudinal cross-sectional view showing one embodiment of the high-temperature reactor of the present invention as a vertical furnace; FIG. 2 is a diametrical cross-sectional view showing another embodiment of the high-temperature reactor of the present invention as a model furnace; FIG. 3 is a perspective view showing an example of the internal configuration when the high temperature reactor of the present invention is used as a model furnace.

1 is a cylindrical chamber made of, for example, SUS, the outer wall is formed into a double wall, and a cold water port 2 and a cold water outlet 3 are provided for passing cooling water inside;
Since the reaction in Method D is processed at a high temperature of 1450°C or higher, heat radiation to the outside of the chamber 1 can be alleviated, and one end of the chamber 1 can be attached and detached in an airtight state via an O-ring 4. It's at your disposal. 5 is a reaction chamber made of, for example, graphite and shaped like a box, with a bottom surface (
Or, the left side plate) 5-1 is provided with a reaction gas introduction hole 7 to which the reaction gas introduction pipe 6 is connected, and the upper surface (or the right side plate)
5-2 is provided with an exhaust hole 8, is fixed to the chamber 1 via a fixed member 9, and has a molded member 10 attached to the center of the interior.
The surrounding area can be filled with a reactive gas. 11
is a partition wall made of an insulating material and provided adjacent to the outer wall surface of the reaction chamber 5 so that heat can be efficiently transferred to the reaction chamber 5. 12 is a heating chamber,
A heating element 13 made of graphite is formed between the partition wall 11 and the chamber 1, is fixedly attached to the chamber 1 through an insulating member 14, and connected to a power source (not shown), and an inert gas is introduced. An introduction hole 16 to which a pipe 15 is connected is provided, and an inert gas is supplied to a gas pressure regulator (not shown).
The gas pressure is adjusted and introduced, and the internal pressure of the heating chamber 12 can be made higher than the internal pressure of the reaction chamber. Reference numeral 17 denotes an exhaust pipe connection part, which is connected to an exhaust fan (not shown) and sucks the reactor.

The high-temperature reactor of the present invention has a vertical type as shown in FIG.
Alternatively, it can take the form of either of the models shown in FIGS. 2 and 3, and the heating chambers 12 may be attached not only to the left and right sides of the reaction chamber 5, but also to either the top, the bottom, or both. In this case, the heating element 13 provided on the upper side, the lower side, or both sides can be of small capacity as an auxiliary element. Also, the partition wall 11
may be formed so that the reaction chamber 5 and heating chamber 12 are surrounded by an insulating material.

The production of ceramic materials in the present invention is carried out using such a high-temperature reactor. In the present invention, the gas pressure is adjusted and an inert gas such as argon gas is introduced into the heating chamber 12 through the inert inlet pipe 15. By introducing
The internal pressure of the heating chamber 12 is 2 to 5 To lower than the internal pressure of the reaction chamber 5.
This is to maintain and heat the heating element at a temperature of about rr, which prevents corrosive reaction gas and generated scum in the reaction chamber 5 from penetrating into the heating chamber 12 and corroding and deteriorating the heating element 13. This is something that can be prevented.

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

In the example, the inner diameter is 850 rran, which allows cooling water to pass through the mold outer wall layer.
Width 300ITIIT+ and length 400mm fixed with fixed members in a SO3 chamber with a length of 1300℃my+
A graphite heating chamber with a graphite heating element fixed thereon was installed in the center of a graphite reaction chamber with a diameter of 250 m and a thickness of 10 m + n as a mold material in the center of a graphite reaction chamber with a height of 300 m and a height of 5 I.
Using a high-temperature reactor equipped with a reaction gas introduction pipe and an inert gas introduction pipe made by connecting JS and graphite,
13cj32005CCH as a reaction gas in the reaction chamber,
BN was synthesized on the mold material by introducing NH31000SCC)l through the reaction gas introduction pipe and reacting at 1900° C. and I Torr for 5 hours. During this time, argon gas was introduced into the heating chamber through an inert gas introduction pipe, and the flow rate of argon gas was varied from 0 to 15008 CC)f, and the pressure inside the heating chamber was maintained at 2 Torr higher than the pressure inside the reaction chamber.

After the reaction is complete, measure the degree of damage to the heating element as the weight loss of the heating element. The results are shown in Table 1. By using the high temperature reactor of the present invention and introducing an appropriate amount of inert gas into the heating chamber according to the manufacturing method of the present invention, the pressure in the heating chamber is made higher than the pressure in the reaction chamber. It has been found that it is possible to significantly reduce the degree of corrosion damage to graphite heating elements.

Table 2 The results are as shown in Table 2, which shows that the degree of corrosion damage to graphite heating elements can be significantly reduced by the present invention and the manufacturing method of the present invention using a high-temperature reactor. This was recognized.

Table 2 Note: Severe damage means a weight loss of 10-20%, moderate damage means a weight loss of 5-9%, and light damage means a weight loss of less than 5%. , NH3, Boo 5CCH, SiCρ,
80 SCCM, H27005CCI4, 1500
Except for reacting for 5 hours at ℃ and 10 Torr.
It was treated in the same manner as in Example 1, and the degree of damage to the heating element was measured in the same manner as in Example 1.

[Effects of the Invention] The present invention, when producing ceramic materials by a chemical vapor phase reaction method, introduces an appropriate amount of inert gas into a pressurizing chamber to maintain the internal pressure of the heating chamber higher than the internal pressure of the reaction chamber. This is a production method in which the reaction is carried out using a high-temperature reactor.
SIC, Si3N4. Excellent effects have been recognized, such as making it possible to significantly reduce the degree of damage to heating elements in high-temperature reactors used in the production of ceramic materials such as BN, stabilizing product quality, and making it possible to reduce costs.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing one embodiment of the high-temperature reactor of the present invention as a vertical furnace; FIG. 2 is a diametrical cross-sectional view showing another embodiment of the high-temperature reactor of the present invention as a model furnace; FIG. 3 is a perspective view showing an example of the internal configuration when the high-temperature reactor of the present invention is a horizontal furnace. DESCRIPTION OF SYMBOLS 1... Chamber, 2... Cold water inlet, 3... Cold water outlet, 5... Reaction chamber, 6... Reaction gas introduction pipe, 9...
...Fixed member, 10... Shape material, 11... Partition wall, 12
...Heating chamber, 13...Heating element, 14...Insulating member, 15...Inert gas introduction pipe, 17...Exhaust pipe connection diagram

Claims (2)

[Claims] (1) In the 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, an inert gas is introduced into a heating chamber in a high-temperature reactor, and the internal pressure of the heating chamber is A method for producing a ceramic material characterized by reacting a reactive gas while maintaining the internal pressure higher than the internal pressure. (2) In a chemical vapor phase reaction processing furnace that introduces a reactive gas and generates ceramic material on a mold material at high temperature, there is a chamber with a cooling capacity through which cold water is passed through the double outer wall, and a fixed member is installed in the chamber. a reaction chamber fixedly installed through the reaction chamber; a partition wall provided adjacent to the outer wall surface of the reaction chamber; a heating chamber provided between the partition wall and the chamber; A fixedly installed heating element, an inert gas introduction pipe that introduces an inert gas whose gas pressure is adjusted by a gas pressure regulator from the outside of the chamber into the heating chamber, and a reactant gas that introduces the reaction gas from the outside of the chamber into the reaction chamber. A high-temperature reactor for manufacturing ceramic materials, characterized in that it is equipped with a reaction gas introduction pipe.