JP2782889B2 - Method for producing fiber-reinforced inorganic material - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a fiber-reinforced inorganic material, and more particularly to a method for obtaining a fiber-reinforced inorganic material having an arbitrary shape and a dense structure. It is about.

"Conventional technology" High-temperature, high-strength, high-toughness, and environmental stability are particularly required in the fields of aircraft, rocket, space, nuclear fusion,
In the energy-related technical field, a fiber-reinforced inorganic material that is a super heat-resistant material is required as a material for a rocket, a jet, a ram jet engine, and an ultra-high temperature heat-resistant wall.

Although it is difficult to provide a material that completely satisfies such uses, a heat-resistant composite material in which a heat-resistant, oxidation-resistant base material tissue layer is adhered to the surface of a carbon-based fiber as a material that partially satisfies such a use. Etc. are being studied.

Conventionally, when manufacturing such a heat-resistant composite material, a plurality of single fibers are aggregated, and a desired shape is formed by a forming method such as filament winding (a method of winding fibers around a core metal), sheet lamination, or multidimensional weaving. Is formed, and the CVI method (Chemical Vapor
A method has been adopted in which a thermochemical reaction is caused while impregnating a gaseous raw material using infiltration to form a heat-resistant base material tissue layer in a fiber molded body to a required thickness. According to the CVI method, there is an advantage that the control of the attached tissue of the base material can be performed relatively easily.

[Problems to be Solved by the Invention] However, in a molding method such as filament winding, sheet lamination, or multidimensional weaving, the shape of a fiber molded body is limited, and only a simple shape can be molded. In addition, a multi-dimensional weaving molding method requires a very long man-hour. On the other hand, even if the composite material after the formation of the base material structure layer is formed by machining or the like, the dense base material structure layer has high hardness and high rigidity, so that it cannot be processed substantially.

The present invention has been proposed in view of the above circumstances, and has an object to have a dense base material structure layer and to enable molding of an arbitrary shape.

"Means for Solving the Problems" In order to achieve the above object, in the present invention, a step of forming a fiber molded body in a state where a plurality of single fibers are aggregated, forming the fiber molded body by a mold, and forming the mold A step of causing a thermochemical reaction while impregnating the fiber molded body with a gaseous raw material from the gap of the mold in a state where the mold is closed to partially form a matrix material in the fiber molded body, and partially forming the matrix material Forming a matrix material layer that fills the voids of the intermediate molded body by causing a thermochemical reaction while impregnating the entire surface with the gaseous raw material after removing the intermediate molded body from the mold. Manufacturing method.

In the manufacturing method of the present invention, the fiber material is formed into a desired shape by a mold, and the matrix material is partially applied to the surface of the single fiber by performing the CVI method from a gap of the mold in a closed state of the mold. An intermediate formed body formed by adhesion is produced. In this state, the intermediate molded body is in a state in which voids are left between the base materials, but the single fibers are bonded to such an extent that the shape does not collapse due to the partially adhered base material. Therefore, even if the intermediate molded body is removed from the mold in this state, the intermediate molded body does not return to its original state, and the shape at the time of molding is maintained. Then, by removing the mold and fully impregnating the entire surface of the intermediate molded body with a gaseous raw material to cause a thermochemical reaction, the voids are filled to form a dense base material structure layer.

"Example" An example of an embodiment of a method for producing a fiber-reinforced inorganic material according to the present invention will be described with reference to Figs. 1 to 3.

[Process of Forming Fiber Molded Body] The fiber to be applied needs to be a fiber having a high-temperature strength suitable for reinforcing an inorganic base material. For example, carbon, silicon carbide, silicon nitride, alumina, It is a fiber mainly composed of zirconia, mullite and other inorganic heat-resistant materials.

In order to manufacture, for example, an afterburner part for an aircraft engine using such fibers, the fibers are formed into, for example, a flat plate by a forming method such as sheet lamination or multidimensional weaving. The fiber molded body 1 obtained by this molding has a plurality of single fibers 1a.
Therefore, as shown in FIG. 1 (B), many voids 1b are provided between the single fibers 1a.

[Embossing and Partial Base Material Forming Step] A mold 3 having a cavity 2 of a desired shape is manufactured from a carbon material, and the fiber molded body 1 is disposed between an upper mold 3A and a lower mold 3B. 1 As shown in FIG. 1 (A), the mold is closed, and compression molding is performed in the cavity 2. And
In order to hold the mold 3 in the mold closed state, the upper mold 3A and the lower mold 3B are fixed by bolts and nuts 4 made of, for example, a carbon material.

Next, as shown in FIG. 2 (A), the fiber molded body 1 together with the mold 3 in the closed mold state is placed in the reaction furnace 5 of the CVI apparatus, and the gas raw material is fed from the gas filling port 5a of the reaction furnace 5 while being sent. The intermediate molded body 6 is produced by performing the above-mentioned CVI method.
In this case, for example, the carbon fiber 1a is fed into the reaction furnace 5 in which a treatment is performed at a high temperature of 1250 ° C. using a hydrocarbon-based gas source, for example, a gas source having a composition of hydrogen-5% methane. The gaseous raw material enters the cavity 2 through the gap of the mold 3 and forms a base material 6a on the surface of the single fiber 1a of the fiber molded body 1 by a thermochemical reaction. The process is stopped when the base material 6a is adhered to 10%.

Then, after taking out the intermediate molded body 6 together with the mold 3 from the reaction furnace 5, the mold 3 is opened and the intermediate molded body 6 is removed from the cavity 2. In this state, the base material 6a is partially
Are adhered and formed, and the voids 6b are mostly left. However, the single fibers 1a are joined by the base material 6a, and the intermediate molded body 6 is held in the shape of the cavity 2 to prevent mold collapse. It will be in the state that was done.

[Full-Scale Base Material Tissue Layer Forming Step] Next, only the intermediate molded body 6 is placed in the reaction furnace 5 of the CVI apparatus, and is set on a carbon cradle or the like.
A thermochemical reaction is caused at a high temperature while impregnating the gaseous raw material from the entire surface of the intermediate molded body 6 to form a base material structure layer (base material) 7 a on the surface of the single fiber 1 a of the intermediate molded body 6. In this case, a mixed gas of a hydrocarbon gas and a silicon-containing gas, for example, a mixed gas of a composition of hydrogen-8% methane-10% silicon tetrachloride is used as a gas raw material, and silicon It is formed as a material.

In this process, the base material 7a adheres and grows like a concentric annual ring on the surface of the single fiber 1a by being able to accurately control the adhering tissue of the base material 7a as described above. Is gradually filled. Then, this step is continued until the void 6b disappears and the open porosity becomes 0%.

The fiber reinforced material 7 manufactured in this manner is reinforced with carbon fiber, and can exhibit high strength by using a composite material based on carbon and silicon carbide. Therefore, an arbitrary shape corresponding to the cavity 2 of the mold 3 can be obtained, and in the final step of forming the base material structure layer 7a, the intermediate molding is performed while the mold 3 is removed. The entire surface of the body 6 is impregnated with the gaseous raw material, so that the inner fiber 1a can be reliably surrounded by the base material tissue layer 7a to obtain a dense structure. Therefore, it exhibits properties superior in heat resistance and the like to conventional metal parts.

[Effects of the Invention] As is clear from the above description, the following effects can be obtained according to the method for producing a fiber-reinforced inorganic material according to the present invention.

(I) By partially forming the matrix material in the fiber molded body with the mold closed, the single fibers can be bonded to such an extent that the mold does not collapse due to the matrix material, and the fiber is restored after being removed from the mold. Therefore, it can be formed in an arbitrary shape such as a plurality of shapes.

(Ii) Since the matrix material layer is formed while being impregnated with the gaseous raw material from the entire surface after the mold is removed from the mold, the voids can be filled in a state in which the internal single fibers are also securely surrounded, and a dense structure can be obtained. Strength and quality as a composite material can be improved.

[Brief description of the drawings]

1 to 3 show an example of an embodiment of a process for producing a fiber-reinforced inorganic material according to the present invention. FIG. 1 (A) is a front sectional view showing a state in which a fiber molded body is molded by a mold. FIG. 1 (B) is an enlarged transverse sectional view of the fiber molded body at that time, FIG. 2 (A) is a front sectional view showing a state in which a base material is formed in a mold closed state, and FIG. ) Is an enlarged cross-sectional view of an intermediate molded body in a state where a base material is partially formed, and FIG. 3A shows a state in which a base material tissue layer is formed in the intermediate molded body after being removed from a mold. FIG. 3 (B) is an enlarged cross-sectional view of the fiber-reinforced inorganic material after forming the base material tissue layer. 1 ... fiber molded body, 1a ... single fiber, 1b ... void, 2 ...
Cavity, 3 ... mold, 4 ... bolt / nut, 5 ...
Reaction furnace, 6: Intermediate molded body, 6a: Base material, 6b: Void, 7a: Base material structure layer (base material), 7: Fiber-reinforced inorganic material.

Continuation of the front page (72) Inventor Takashi Onami 3-1-1-15 Toyosu, Koto-ku, Tokyo Ishikawajima Harima Heavy Industries, Ltd. Technical Research Institute (56) References JP-A-2-1644781 (JP, A) JP-A Sho 64-87581 (JP, A) JP-A-3-28177 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C04B 35/71-35/84 C04B 38/00-38 / 10 C04B 41/80-41/91

Claims (1)

(57) [Claims] 1. A step of forming a fiber molded body in a state in which a plurality of single fibers are aggregated, forming the fiber molded body by a mold, and closing the mold to form a gaseous raw material from the gap of the mold into the fiber molded body. Forming a base material in the fiber molded body by causing a thermochemical reaction while impregnating the material; and removing the intermediate molded body partially formed from the base material from the mold, and then removing the gaseous material from the entire surface thereof. Forming a base material tissue layer that fills voids of the intermediate molded body by causing a thermochemical reaction while impregnating the intermediate molded body.