JP2004075410A - Ceramic-based composite material having protective layer and its manufacturing process - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ceramic-based composite material having a protective layer which is hardly damaged by cracking, separation, erosion, scattering, reacting, etc., in a high-temperature gas flowing at a high flow rate, does not lose its protective layer during long-term use and is therefore usable in the high-temperature gas for a long time. <P>SOLUTION: The material has a fiber fabric 2 formed from inorganic fibers 1, the protective layer 4 which at least partially covers the outer surface of the fiber fabric and matrices 6 filling gaps between the fibers composing the fiber fabric. Here, the protective layer 4 comprises a felt material wherein the inorganic fibers are mutually intertwined. The matrices 6 are formed between the fibers in the fiber fabric 2 and the protective layer 4 through the same molding means. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a ceramic-based composite material having a protective layer and a method for producing the same.
[0002]
[Prior art]
Since ceramics have high heat resistance but have a brittle defect, ceramic matrix composites (CMC: Ceramic Matrix Composites) reinforced with ceramic fibers have been developed. Further, as a means for enhancing the toughness of such a ceramic-based composite material, a coating of C or BN is generally provided on the fiber surface.
[0003]
However, the oxidation resistance of the C coating is up to about 600 ° C., and the oxidation resistance of the BN coating is up to about 900 ° C. Therefore, when CMC is applied to a high-temperature component that is used at a temperature of about 1000 ° C. or more for a long time, such as a turbine blade of a gas turbine, a combustor, and an afterburner component, there is a problem that the environmental resistance is insufficient and the performance is severely deteriorated. .
[0004]
In order to solve this problem, it has been proposed to coat the outer surface of the CMC with a SiC coating or a glass coating (for example, Japanese Patent Application Laid-Open Nos. 5-128484 and 10-259070).
[0005]
Japanese Patent Application Laid-Open No. 5-124883 discloses a "carbon fiber / carbon composite material" which is a carbon fiber / carbon composite material in which a SiC film is formed as an oxidation-resistant film on the surface to increase oxidation resistance at high temperatures. A composite oxide which is in a semi-molten state at a high temperature is provided as a sealing material.
[0006]
Japanese Patent Application Laid-Open No. H10-259070 discloses "glass-impregnated fiber-reinforced ceramics and a method for producing the same", comprising an inorganic fiber, a ceramic matrix including an inorganic fiber and integrally formed and having a void open to an external space; A glass-impregnated fiber reinforced ceramic comprising a glass matrix formed by closing the voids of the matrix is produced by impregnating the voids with a glass precursor solution and performing a heat treatment.
[0007]
[Problems to be solved by the invention]
However, in the case of the SiC coating, if it is formed thickly, it breaks and can only be thinly coated. Therefore, when used for a long time, the protective layer is consumed by cracking, peeling, erosion, etc., and the CMC itself is exposed to a high-temperature oxidizing atmosphere. Exposure will damage the CMC.
[0008]
In the case of a glass coating, since the softening occurs at a high temperature, the protective layer disappears due to scattering or reaction in a gas having a high flow rate such as a jet engine, and the CMC is damaged.
[0009]
In addition, cracking and peeling occur due to thermal stress, thermal shrinkage, etc., even with means of coating with a ceramic material by a method such as thermal spraying, and none of them can withstand long-term use.
[0010]
The present invention has been made to solve such a problem. That is, the object of the present invention is that, in a high-temperature gas with a high flow velocity, it is hardly damaged by crack generation, peeling, erosion, scattering, reaction, etc., and the protective layer does not disappear over a long period of use. An object of the present invention is to provide a ceramic-based composite material having a protective layer that can be used for a long time in a ceramic substrate.
[0011]
[Means for Solving the Problems]
ADVANTAGE OF THE INVENTION According to this invention, the fiber fabric (2) shape | molded by the inorganic fiber (1), the protective layer (4) which covers at least one part of the outer surface of this fiber fabric, and the clearance gap between the fibers which comprise a fiber fabric And a matrix (6) that fills the matrix, and wherein the protective layer is a felt material in which inorganic fibers are entangled with each other.
[0012]
Further, according to the present invention, a fiber woven fabric forming step (12) of forming a fiber woven fabric (2) with the inorganic fiber (1), and protection of covering at least a part of the outer surface of the fiber woven fabric with the protective layer (4). A layer forming step (14) and a matrix forming step (16) for filling gaps between fibers constituting the fiber fabric with a matrix (6), wherein the protective layer is a felt material in which inorganic fibers are entangled with each other. A method for producing a ceramic-based composite material having a protective layer is provided.
[0013]
According to the ceramic-based composite material of the present invention and the method for producing the same, the protective layer (4) made of a felt material in which inorganic fibers are entangled with each other is formed so as to cover at least a part of the outer surface of the fiber fabric (2). You.
The protective layer (4) is made of the same material as the inorganic fibers (1) constituting the CMC, and is integrated in the matrix forming step (16). Peeling hardly occurs.
[0014]
Further, even in the case of shaving by erosion or the like, unlike conventional SiC coating or the like, since the thickness is increased by one digit or more due to the thickness of the felt material, the life can be extended by that much.
Further, since the protective layer (4) is made of the same material as the inorganic fibers (1) constituting the CMC, there is almost no difference in thermal expansion, and cracks due to thermal stress are reduced by the CMC made of fibers in the felt state. Therefore, the fracture is limited to the local fracture, and the fracture reaching the CMC made of the fiber fabric (2) is unlikely to occur, and the durability is improved accordingly.
[0015]
Therefore, it is hard to be damaged by crack generation, peeling, erosion, scattering, reaction, etc. in high temperature gas with high flow velocity, and the protective layer does not disappear over long time use, so that it can be used in high temperature gas for a long time It becomes.
[0016]
According to a preferred embodiment of the present invention, the fibrous fabric (2) and the protective layer (4) are stitched in close contact with each other by inorganic fibers, and the matrix (6) is formed of the stitched fibrous fabric (2). ) And the fibers of the protective layer (4) are formed by the same molding means.
[0017]
In the protective layer forming step (14), the fiber woven fabric (2) and the protective layer (4) are stuck to each other with inorganic fibers in close contact with each other and sewn in the matrix forming step (16). ) And the fibers of the protective layer (4) form a matrix (6) by gas phase impregnation, polymer impregnation or a combination thereof.
[0018]
Further, after suturing the fiber fabric (2) and the protective layer (4) with the inorganic fiber, both the fiber fabric (2) and the protective layer (4) are formed by the same molding means using gas phase impregnation, polymer impregnation, or a combination thereof. By forming the matrix (6) between the fibers, the bonding strength therebetween can be further increased.
Further, by changing the degree of porosity by controlling the CMC of the protective layer, a heat shielding effect can also be imparted.
[0019]
After the matrix forming step (16), it is preferable that the protective layer is impregnated with a glass or an antioxidant that becomes oxidized and vitreous in the porous portion.
This method can be used as a protective layer in which glass or the like is impregnated in a porous portion, and is particularly useful for preventing scattering of glass.
As shown in FIG. 1 (B), the same protective layer forming step (14) is performed after the ceramic-based composite material is manufactured, and the matrix forming step (16) is performed only on the protective layer portion. Layers can be obtained. This method is also useful as a method for reshaping the protective layer after use.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1A is a flowchart showing a method for producing a ceramic-based composite material of the present invention. As shown in this figure, the method of the present invention comprises a fiber fabric forming step 12, a protective layer forming step 14, and a matrix forming step 16.
[0021]
In the fiber fabric forming step 12, a fiber fabric having a predetermined shape is formed using the inorganic fibers 1 (for example, SiC fibers). The shape to be formed in this step is preferably a three-dimensional shape suitable for high-temperature components used for a long time at a high temperature (for example, about 1000 ° C. or higher), such as turbine blades, combustors, and afterburner components to be applied. It may be shaped.
[0022]
In the protective layer forming step 14, at least a part of the outer surface of the fiber fabric is covered with the felt material using a felt material in which the inorganic fibers are entangled with each other in the felt coating step 14a. Next, in the suturing step 14b, the fiber fabric 2 and the protective layer 4 are stitched together with the inorganic fibers 1 in close contact with each other. In the case of FIG. 1A as well, if the joining strength of the matrix is sufficient, the suturing step 14b may be omitted.
Further, in this example, an interface layer (for example, C (carbon)) is formed on the surface of the inorganic fiber 1 by the interface forming step 15.
[0023]
In this example, the matrix forming step 16 is a step of filling gaps between fibers constituting the fiber woven fabric with the matrix 6, and in this example, comprises a gas phase impregnating step 16a, a polymer impregnating step 16b, and an inert baking step 16c. .
[0024]
The gas-phase impregnation step 16a is a step of performing treatment by a CVI method (Chemical Vapor Infiltration method), in which a fabric fixed by a special jig is heated in a furnace, and methyltrichlorosilane flows in a reduced-pressure atmosphere. To synthesize SiC.
[0025]
Next, in the polymer impregnation step 16b, for example, the organic silicon polymer is dissolved in a solvent such as xylene to impregnate the fabric after gas phase impregnation. The main component of the organosilicon polymer is preferably polycarbosilane.
Next, in an inert firing step 16c, the organic silicon polymer is converted into SiC by firing at a high temperature of about 1200 ° C. in an inert gas (for example, nitrogen gas). The polymer impregnation step and the inert baking step are preferably performed alternately and repeatedly.
[0026]
The machining step 17 is a step of machining or surface-grinding the ceramic-based composite material completed in the matrix forming step 16 to produce a desired gas turbine component or the like. In this step, the workpiece is processed into a predetermined shape using, for example, a diamond grindstone.
[0027]
The outer surface coating synthesizes SiC by CVI or the like in order to protect a machined surface or the like.
[0028]
Further, as shown in FIG. 1B, the same protective layer can be obtained by performing the protective layer forming step 14 and performing the matrix forming step 16 only on the protective layer portion even after the ceramic-based composite material is manufactured. Can be done. This method is also useful as a method for reshaping the protective layer after use.
[0029]
FIG. 2 is a schematic diagram of the ceramic-based composite material of the present invention manufactured by the method described above. In this figure, (A) is a turbine blade as an example of a high-temperature component, (B) is a BB cross-sectional surface thereof, and (C) is an enlarged view of a part thereof (A portion).
[0030]
In the example of FIG. 2B, the entire outer surface of the high-temperature component (turbine blade) is covered by the protective layer 4, but the present invention is not limited to this, and it is sufficient if at least a part of the outer surface is covered. . As the high-temperature parts, high-temperature parts that are used for a long time at about 1000 ° C. or more, such as turbine blades of gas turbines, combustors, and afterburner parts, are suitable. However, the present invention is not limited to this. Applicable to all CMC parts. For example, the protective layer 4 may be provided only on the inner surface of the shroud component of the gas turbine.
[0031]
As shown in FIG. 2 (C), the ceramic-based composite material of the present invention includes a fiber fabric 2, a protective layer 4, and a matrix 6.
[0032]
The fiber fabric 2 is a three-dimensional or planar fabric formed of the inorganic fiber 1 (for example, SiC fiber). The fiber fabric 2 is preferably a three-dimensional weave of the inorganic fibers 1, but may be another fabric.
[0033]
The protective layer 4 is a felt material in which the inorganic fibers 1 ′ are intertwined with each other, and covers at least a part of the outer surface of the fiber fabric 2. The felt material is a material in which relatively short inorganic fibers 1 'are randomly entangled in a plane, and most fibers extend in the plane direction. The fibers may include fibers extending in the thickness direction. Alternatively, a flat woven fabric may be formed of relatively long inorganic fibers 1 ′, which may be laminated and sewn with another fiber in the thickness direction.
[0034]
It is preferable that the inorganic fibers 1 ′ constituting the protective layer 4 are the same as the inorganic fibers 1 (for example, SiC fibers) of the fiber fabric 2. However, the present invention is not limited to this, and the fiber composition, thickness, length, and the like may be different.
[0035]
In FIG. 2C, the fiber fabric 2 and the protective layer 4 are stitched in close contact with each other by inorganic fibers 1 '. However, the present invention is not limited to this, and this stitching may be omitted if the joining strength of the matrix is sufficient.
[0036]
The matrix 6 fills gaps between the fibers constituting the fiber fabric 2 and the protective layer 4. As described above, the matrix 6 is formed by the same forming means after the textile fabric 2 and the protective layer 4 are stitched.
[0037]
According to the present invention described above, the protective layer 4 made of a felt material in which inorganic fibers are entangled with each other is formed so as to cover at least a part of the outer surface of the fiber fabric 2.
The protective layer 4 is made of substantially the same material as the inorganic fibers 1 constituting the CMC, and is integrated in the matrix forming step 16, so that the protective layer 4 has the same adhesion as the inside of the CMC, and is separated only by the protective layer. Is unlikely to occur.
[0038]
Also, even when the material is cut by erosion or the like, unlike the conventional SiC coating or the like, since the thickness of the felt material is increased by one digit or more, the life can be extended correspondingly.
[0039]
Furthermore, since the protective layer 4 is made of the same material as the inorganic fibers 1 constituting the CMC, there is almost no difference in thermal expansion, and cracks due to thermal stress are caused by the CMC composed of fibers in a felt state. However, the fracture is limited to the local fracture, and the fracture reaching the CMC made of the fiber fabric 2 is unlikely to occur, and the durability is improved accordingly.
[0040]
Therefore, it is hard to be damaged by crack generation, peeling, erosion, scattering, reaction, etc. in high temperature gas with high flow velocity, and the protective layer does not disappear over long time use, so that it can be used in high temperature gas for a long time It becomes.
[0041]
Further, after suturing the fiber fabric 2 and the protective layer 4 with inorganic fibers, the matrix 6 is formed between the fibers of both the fiber fabric 2 and the protective layer 4 by the same molding means using gas phase impregnation, polymer impregnation, or a combination thereof. By doing so, the joining strength between them can be further increased.
Further, by changing the degree of porosity by controlling the CMC of the protective layer, a heat shielding effect can also be imparted.
[0042]
Further, it can be used as a protective layer in which a porous portion is impregnated with glass or the like, and is particularly useful for preventing scattering of glass.
[0043]
It should be noted that the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made without departing from the spirit of the present invention.
[0044]
【The invention's effect】
As described above, the ceramic-based composite material having the protective layer of the present invention and the method of manufacturing the same are less likely to be damaged by crack generation, peeling, erosion, scattering, reaction, etc. Has an excellent effect such that the protective layer does not disappear in the use of, and is used for a long time in a high-temperature gas.
[Brief description of the drawings]
FIG. 1 is a flowchart showing a method for producing a ceramic-based composite material of the present invention.
FIG. 2 is a schematic view of a ceramic-based composite material of the present invention.
[Explanation of symbols]
1, 1 'inorganic fiber, 2 fiber fabric, 4 protective layer, 6 matrix,
12 fiber fabric forming step, 14 protective layer forming step,
14a felt coating process, 14b suturing process,
15 C-CVI step, 16 matrix forming step,
16a gas phase impregnation step, 16b polymer impregnation step,
16c inactive firing step, 16d oxidation firing step,
17 Machining process, 18 Glass impregnation process

Claims (5)

Fiber woven fabric (2) formed of inorganic fibers (1), protective layer (4) covering at least a part of the outer surface of the fiber woven fabric, and matrix (6) for filling gaps between fibers constituting the fiber woven fabric Wherein the protective layer is a felt material in which inorganic fibers are intertwined with each other. The textile fabric (2) and the protective layer (4) are sewn in close contact with each other by inorganic fibers, and the matrix (6) is formed between the sewn textile fabric (2) and the fibers of the protective layer (4). The ceramic matrix composite material according to claim 1, wherein the ceramic matrix composite material is formed by the same molding means. A fiber woven fabric forming step (12) of forming the fiber woven fabric (2) with the inorganic fiber (1), a protective layer forming step (14) of covering at least a part of the outer surface of the fiber woven fabric with the protective layer (4), A matrix forming step (16) of filling gaps between fibers constituting the fiber woven fabric with a matrix (6);
The method for producing a ceramic-based composite material having a protective layer, wherein the protective layer is a felt material in which inorganic fibers are entangled with each other. In the protective layer forming step (14), the textile fabric (2) and the protective layer (4) are stitched in close contact with each other by inorganic fibers,
In the matrix forming step (16), a matrix (6) is formed between the fibers of the sewn fiber fabric (2) and the protective layer (4) by gas phase impregnation, polymer impregnation, or a combination thereof. The method for producing a ceramic-based composite material according to claim 3. The method for producing a ceramic-based composite material according to claim 4, wherein after the matrix forming step (16), the porous portion is impregnated with a glass or an antioxidant that becomes glassy by oxidation.

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