JPS61141678A - Manufacture of fiber reinforced ceramic shell structure part - 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 relates to a method for manufacturing a fiber-reinforced ceramic shell structural component, and particularly relates to a method for manufacturing a fiber-reinforced ceramic shell structural component obtained using a CVD reaction. .

[Prior art] In recent years, so-called new ceramics such as non-oxide ceramics such as silicon nitride, silicon carbide, and sialon, as well as aluminum oxide and zirconium oxide, have been rapidly focused on as high-temperature, high-strength structural materials, and much research and research has been conducted. development is underway.

These ceramics have many uses as gas turbine blades and combustors, diesel engine cylinders and pistons, and other high-temperature mechanical parts.

However, as is well known, ceramics are brittle materials, and even with the new ceramics mentioned above, cracks propagate faster than metal materials, and they are unreliable, such as being destroyed by the slightest defect, so they require high strength. It has not yet been put to practical use in structural parts.

Conventionally, in order to solve these problems, attempts have been made to improve the strength of ceramic products by mixing inorganic short fibers called whiskers into ceramics.

Furthermore, conventionally, ceramic products have been manufactured by molding ceramic powder raw materials by an appropriate method and then sintering them, but this sintering usually requires a sintering aid. As a result.

This sintering aid reduces the high temperature strength of the entire product. In other words, although the ceramic itself has high strength even at high temperatures, many of the low-melting point sintering aid components gather at the grain boundaries, and as a result, the strength of the resulting product is reduced to a secondary level.
As shown in the figure, it decreases in the high temperature range.

In recent years, completely new ceramic manufacturing methods such as CVD and P
Vapor phase plating methods such as the VD method are in practical use in the field of surface treatment, particularly as a means for forming thin films.

According to the CVD method, it is possible to produce ceramics with an extremely dense structure, and since there is no sintering process in the first place, there is no need to mix sintering aids.Therefore, as shown in Figure 2, the resulting product is It has the advantage that strength does not decrease even in a high temperature range.

[Problems to be Solved by the Invention] Although the brittleness of the ceramic can be improved by mixing whiskers into the ceramic, this method has the disadvantage that it is difficult to uniformly mix the whiskers into the ceramic.
It is not practical because there is a limit to the mixing rate of whiskers and there is also an upper limit to the brittleness improvement effect.

According to the CVD method, since no sintering aid is required, products with the high-temperature strength inherent to ceramics can be obtained;
The VD method has an extremely slow ceramic production rate, with a rate of 20 to 3
Since the film formation rate is about 0 gm/hr, it takes a long time to form a normal structure, which is disadvantageous in that it is not industrially advantageous. Moreover, although ceramic products obtained by the CVD method have high strength, they still have the problem of being brittle.

[Means for Solving the Problems] The present invention has been made to solve the above-mentioned conventional problems, and combines the advantages of the method of reinforcing ceramics with fibers and the CVD method.

That is, one aspect of the present invention is to combine long fibers of SiC and/or carbon in a network to form a long fiber structure of a predetermined shape, supply a CVD reaction gas to the surface of the fibers of the long fiber structure to cause a CVD reaction, The gist of the present invention is a method for manufacturing a fiber-reinforced ceramic lid structure component, characterized in that a ceramic layer is deposited on the surface of the fiber.

The present invention will be explained in detail below.

In the present invention, first, SiC and/or carbon long fibers are used to form a structure into a predetermined shape. In this case, if the structure is similar in shape and hollow to the target part, lightweight fiber-reinforced ceramic 2.
shell structural parts are easily manufactured.

There are no particular restrictions on the method for producing the mesh-like long fiber structure.
Examples include a method of manually or mechanically knitting long fibers, and a method of forming using a heat-resistant binder.

Next, the surface portion of the fibers constituting this network-like long fiber structure is usually heated to a precipitation temperature range for CVD reaction.

The heating method is not particularly limited, but in the case of carbon fibers, high frequency induction heating or the like with a simple device configuration is advantageous. When using high-frequency induction heating, the carbon fiber network structure is made of carbon and is conductive, so it is inserted into the reactor as it is, and an alternating magnetic field is applied using a high-frequency coil. The surface is heated by high frequency induction.

As the heating method, an external heating method in which the reaction vessel is heated from the outside using a fiber material, a laser heating method, etc. can also be adopted.

A CVD reaction gas is supplied to the surface of the fibers of the mesh-like long fiber structure heated in this way to cause a CVD reaction, and a ceramic layer is deposited on the surface.

The ceramics to be deposited include silicon nitride, silicon carbide,
Sialon etc. are suitable. Further, the thickness of the ceramic layer to be formed can be adjusted as appropriate by adjusting the supply amount or heating time of the CVD reaction gas.

In this way, the present invention prepares a network structure of long fibers of SiC and/or carbon, and then deposits ceramic on the fiber surface of this structure by CVD to coat the long fibers with ceramic. However, if the amount of ceramic coating is increased, a structure in which fibers are embedded inside the ceramic is obtained, and a fiber-reinforced ceramic shell structure can be obtained.

[Function] According to the method of the present invention, it is possible to manufacture a member in which SIC and/or carbon long fibers are composited with ceramic, and the brittleness of the ceramic is significantly improved. Furthermore, by employing the CVD method, the high temperature strength of the ceramic layer is maintained at a high level.

In addition, if a shell-like long fiber structure with a similar shape that is slightly smaller than the external shape of the target part is produced and used, the resulting part will be a shell structure with a hollow interior. Therefore, it is lightweight and has excellent high-temperature strength. In addition, CV
When performing the D reaction treatment, the CVD reaction can proceed on both the front and back sides of the shell-like long fiber structure, thereby doubling the growth rate of the ceramic layer and shortening the manufacturing time. Furthermore, if the long fiber structure has a fine mesh, the mesh can be filled with just a small amount of precipitated ceramic, making production easier.

[Example] The present invention will be explained in more detail below using Examples.

Example 1 A rotor blade 3 for a gas turbine shown in FIG. 1 was manufactured according to the manufacturing method of the present invention.

Fig. 1 (&) is a partial sectional view of a gas turbine rotor blade showing an example of a fiber-reinforced ceramic shell structural component manufactured by the method of the present invention, and Fig. 1 (b) is a line BB in Fig. 1 (a). It is an enlarged view of a cross section. In FIG. 1, a rotor blade 1 is formed by providing a ceramic rag coating 3 on a long fiber structure 2 of carbon fibers using the CVD method.

First, carbon fiber (average diameter 0.1 mm,
A mesh-like long fiber structure 2 having an average fiber length of 30 mm and having a shape slightly smaller than and similar to the rotor blade of a gas turbine was formed. This long fiber structure 2 was placed in a container whose atmosphere could be controlled, and heated by a high frequency coil through which a high frequency current of 500 KHz was passed. The temperature was detected by a thermocouple set near the mesh structure, and the temperature of the heating section was maintained at 1300 to 1400°C.

On the other hand, after replacing the inside of the container with inert gas, CHaSi
CH35iCJL3 gas was introduced into the container, and CH35iCJL3 gas was supplied to the heating surface of the network structure. CH3S i
The C1z gas was decomposed in the surface heating section, and SiC was precipitated. After continuing the precipitation reaction, gas supply and heating were stopped, and then the mixture was gradually cooled.

According to the method of the present invention, ceramic rotor blades can be manufactured in a short time, and the resulting rotor blades are lightweight and have extremely high strength.

[Effects] As detailed above, according to the method for manufacturing fiber-reinforced ceramic shell structural parts of the present invention, the strength and formability of the product are significantly improved due to the strength-improving effect of the long fibers of StC and/or carbon. , durability and reliability are enhanced. Furthermore, by employing a shell-like structure made of long fibers, the product can be made into a thin shell structure, thereby making it possible to reduce the weight of the product. Furthermore, since the ceramic layer formed on the long fibers is obtained by CVD reaction, it has extremely high strength even in a high temperature range. Moreover, when using a shell-like structure of long fibers, the CVD reaction can be carried out on both the front and back sides of the long fiber structure.
Since it can be performed on a surface, the ceramic layer can be formed in a short time and production efficiency is high.

Therefore, according to the present invention, it is possible to efficiently manufacture ceramic structural parts with extremely high strength and durability, and the resulting ceramic structural parts can be made lightweight, and can be used for turbine blades, etc. It can be applied to the manufacture of various structural parts, such as the manufacture of high-speed rotating parts.

[Brief explanation of the drawing]

FIG. 1 (11) is a partial cross-sectional view of a gas turbine rotor blade showing an example of a fiber-reinforced ceramic shell structural component manufactured by the method of the present invention, and FIG. B-B
FIG. 2, an enlarged view of a line cross section, is a graph showing the relationship between temperature and strength in a high temperature range of ceramic products obtained by the CVD method and the sintering method. l... Moving blade. 2. Fist/long fiber structure, 3. Ceramic coating. Agent Patent attorney Tsuyoshi Shigeno (a) Igai (C)

Claims (2)

[Claims] (1) SiC and/or carbon long fibers are combined in a network to form a long fiber structure of a predetermined shape, and a CVD reaction gas is supplied to the surface of the fibers of the long fiber structure to cause a CVD reaction. A method for manufacturing a fiber-reinforced ceramic shell structure component, characterized by depositing a ceramic layer on the surface. (2) The fiber-reinforced ceramic shell according to claim 1, wherein the long fiber structure is slightly smaller than the outer shape of the target structural component and has a similar shape to the outer shape of the target structural component. Method of manufacturing structural parts.