JPS6220156B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a heating furnace for SiC coating.

Conventionally, the method of coating SiC on the surface of a substrate to be treated is as follows: (1) A raw material gas consisting of a C source and a Si source is introduced from the outside and heated under normal pressure to form a SiC layer on the surface of the substrate to be treated. (2) When the substrate to be treated is carbon, a raw material gas consisting only of a Si source is introduced from the outside and heated under normal pressure to directly react the C and Si of the substrate to form a SiC layer. The method of forming the material is adopted.

However, in the case of method (1) above, the SiC film does not penetrate into the substrate to be treated, and a uniform and homogeneous SiC film cannot be formed, so the disadvantage is that the SiC film may peel off or crack during use. There is. Also,
Since the Si source used in this method needs to be vaporized at a relatively low temperature, expensive halogen silicon must generally be used.

On the other hand, in the method (2) above, a strong SiC film can be formed because Si is directly reacted with the substrate to be treated (carbon substrate), but the thickness of the SiC film is limited and the range of use is limited. In addition, the properties of the SiC film formed are greatly influenced by the structure and characteristics of the carbon base material.
In order to form a dense SiC film, the carbon base material used must be carefully selected, leading to an increase in costs.

The present invention was made in order to eliminate the above-mentioned drawbacks, and it is possible to achieve good adhesion to the substrate to be treated without using an expensive Si source and without carefully selecting the substrate to be treated.
The present invention aims to provide a heating furnace for SiC coating that can form a SiC film with excellent density, uniformity, and homogeneity.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

In the figure, 1 is a cylindrical furnace body, and a partition plate 2 is interposed in this furnace to divide the inside of the furnace into upper and lower parts. A generation chamber 4 is formed. This partition plate 2
A large number of communication holes 5...5 are provided in the chambers 3 and 4 to form communication paths between the chambers 3 and 4. A cylindrical graphite heating element 6 is disposed in the reaction chamber 3, and a carbon plate 7 as an internal structure is disposed between this heating element 6 and a carbon base material 16 as a substrate to be treated.
A and 7b are installed. On the other hand, a container 8 made of graphite, for example, that accommodates silica such as silica stone and carbon as a raw material for generating a SiO-containing gas is installed in the SiO generation chamber 4, and a coil-shaped heat generating The body is wrapped.

The container 8 is adapted to be taken in and taken out through an opening/closing lid (not shown) provided on the lower side wall of the furnace body 1.

Further, a flange 10 is provided at the upper end of the furnace body 1, and a water cooling lid 11 is attached to this flange 10.
are airtightly fixed via an O-ring 12 made of silicone rubber. This water-cooled lid 11 has the reaction chamber 3
An exhaust pipe 13 is inserted so as to communicate with the
Further, the exhaust pipe 13 is provided with a pressure reducing device, for example, a vacuum pump 14, which exhausts the gas in the reaction chamber 3 to reduce the pressure. Note that 15 in the figure is a shield provided on the inner wall surface of the furnace body 1 to protect it.

Next, the operation of the SiC coating heating furnace having the above-described structure will be explained.

First, a carbon substrate 16 as a substrate to be treated is loaded into the reaction chamber 3 in the furnace, and the outer periphery of the container 8 containing the silica powder 17 and carbon powder 18 installed in the SiO-containing gas generation chamber 4 is heated. When electricity is applied to the provided coil-shaped heating element 9, the following reactions mainly occur.
SiO-containing gas is produced.

SiO ₂ +C→SiO+CO In this way, SiO-containing gas is generated, and if the cylindrical graphite heating element 6 in the reaction chamber 3 is energized and the vacuum pump 14 is operated at the same time, the detailed phenomenon cannot be explained, but it is probably as follows. It is assumed that this is occurring. That is, the SiO-containing gas flowing into the reaction chamber 3 from the generation chamber 4 as shown by the arrow reacts with the carbon plates 7a and 7b serving as the internal structure of the reaction chamber 3 heated to a high temperature, thereby producing Si gas, CO gas etc. are generated. In this generation process, Si gas reacts directly with the carbon base material 16 in the reaction chamber 3, or Si gas and CO gas react near the surface of the carbon base material 16, resulting in the formation of SiC on the surface of the base material 16. A film is formed. The plate-shaped body also serves to protect the heater from SiO-containing gas, etc., and prevents the heater from reacting with SiO-containing gas and being consumed by oxidation, and also forms a SiC film on the heater surface. This suppresses the temperature unevenness within the reaction chamber that occurs due to this, and allows the inside of the reaction chamber to be kept at a uniform temperature, making it possible to form a uniform SiC film. Moreover, it was manufactured using the heating furnace of the present invention.
In the reaction process of the above-mentioned generated gas, the SiC formation is
The inside of the reaction chamber 3 is depressurized by the evacuation action of the vacuum pump 14, and the reactants of the generated gas do not precipitate in large quantities on the surface of the carbon base material 16 at once, but gradually, so that they are dense and homogeneous on the surface of the carbon base material 16. , a uniform SiC film can be formed, and the adhesion of the SiC film to the carbon substrate can be improved.

Note that the plate-shaped body in the heating furnace of the present invention is not limited to the carbon material as in the above embodiments, but may be made of a silicon carbide material. In this case, although a detailed explanation cannot be given, as in the case of carbon, the SiO-containing gas flowing from the generation chamber 4 into the reaction chamber 3 as shown by the arrow is a silicon carbide plate heated to a high temperature. reacts, Si
Gas, CO gas, etc. are generated. The Si source and C source gases generated in this way react directly with the carbon base material 16, or Si gas and CO gas react near the base material surface, forming a SiC film on the surface of the carbon base material. be done.

Further, the shape of the plate-like body may be a combination of plate-like bodies, a cylindrical body, or any other suitable shape.

The partition plate in the heating furnace of the present invention has a reaction chamber and
Any shape may be used as long as it partitions the SiO-containing gas generation chamber, and its shape does not need to be particularly plate-like, and may be any shape.

The heater in the heating furnace of the present invention may not be provided separately for the reaction chamber and the production chamber as in the above-mentioned embodiments, but may be an integrated heater for heating each chamber.

The substrate to be treated in the present invention is not limited to the carbon material as in the above embodiments, but may be formed from a silicon carbide material or the like.

It goes without saying that the heating furnace structure of the present invention can be modified in various other ways without departing from the gist of the present invention.

As detailed above, according to the present invention, it is possible to form a SiC film that has good adhesion to the substrate to be processed and has excellent density, uniformity, and homogeneity using extremely inexpensive raw materials made of silica and carbon. SiC with extremely high practical value
A heating furnace for coating can be provided.

[Brief explanation of the drawing]

The figure is a sectional view of a heating furnace for SiC coating showing one embodiment of the present invention. 1... Furnace body, 2... Partition plate, 3... Reaction chamber,
4... Generation chamber, 6... Graphite heating element, 7a, 7b...
... Carbon plate-shaped body (internal structure), 8 ... Container, 9
... Coiled heating element, 16 ... Substrate to be treated.

Claims (1)

[Claims] 1 Consisting of a furnace body forming a furnace shell, and an internal structure provided inside the furnace and consisting of at least a partition plate and a plate-like body, the part or whole of which is made of carbon or SiC, and the partition plate is a reaction chamber. and a SiO-containing gas generation chamber are interposed to partition the inside of the furnace and form a communication path between each chamber, and a storage container for a SiO-containing gas generation raw material is installed in the SiO generation chamber, and A heater provided to heat the SiO generation chamber and a pressure reducing device for reducing the pressure in the reaction chamber are provided, and the plate-shaped body is provided between at least the substrate to be treated and the heater. Characteristic heating furnace for SiC coating.