JP2020083737A - Method for production for ceramic-based composite material - Google Patents

Abstract

To provide a production method for a ceramic-based composite material restraining of the strength degradation of that material.SOLUTION: A production method for a ceramic-based composite material comprises: an impregnation step S16 of impregnating a polymer 30 as a precursor in a woven cloth having plural ceramic-made fibers 24 and the interlayers 26 covering the peripheries of the fibers 24 to form an elemental body 100; an oxygen supply step S18 of supplying oxygen to the polymer 30 included in the elemental body 100; an inert gas firing step S20 of reacting a polymer 30A by heating an elemental body 100A under an inert gas atmosphere to form a matrix 30B; and an oxygen firing step S22 of removing the interlayer 26 by heating an elemental body 100B under an oxygen atmosphere after the oxygen supply step S18 and the inert gas firing step S20 to generate the ceramic-based composite material 102 in which the matrix 30B is disposed between the fibers 24.SELECTED DRAWING: Figure 6

Description

The present invention relates to a method for manufacturing a ceramic matrix composite material.

Use of ceramic matrix composites (CMC: Ceramic Matrix Composites) is being considered for parts of aircraft bodies and engines of airplanes, industrial gas turbine engines that reach high temperatures and parts that are lightweight and require high durability. . The ceramic-based composite material has a woven fabric having a plurality of fibers and a reinforcing material called a matrix filled in a gap between the fibers. In obtaining the ceramic-based composite material, as an example, a technique called PIP method (Polymer Ignition and Pyrolysis method) is used. The PIP method includes the steps of impregnating a woven fabric with a precursor in a solution containing a matrix precursor and firing the woven fabric impregnated with the precursor.

If the fibers of the woven cloth and the precursor are fired while being in contact with each other, the fibers may be deteriorated by the precursor and the strength of the finished ceramic-based composite material may be reduced. Therefore, for example, as shown in Patent Document 1, the precursor may be impregnated with a woven fabric having a carbon interface layer formed around the fibers, followed by firing. By forming the interface layer around the fiber, contact between the fiber and the precursor is suppressed.

JP, 2018-95484, A

However, even if the precursor is impregnated with a woven fabric having an interface layer formed around the fibers and then the precursor is fired, it may not be possible to fire appropriately, and the strength reduction of the ceramic matrix composite material may not be suppressed. . Therefore, it is required to suppress the strength reduction of the ceramic matrix composite material.

The present invention solves the above-mentioned problems, and an object of the present invention is to provide a method for producing a ceramic-based composite material that can suppress the strength reduction of the ceramic-based composite material.

In order to solve the above-mentioned problems and to achieve the object, a method for producing a ceramic-based composite material according to the present disclosure provides a woven fabric having a plurality of ceramic fibers and an interface layer that covers the periphery of the fibers, By impregnating a polymer as a body to form an elementary body, an oxygen supplying step of supplying oxygen to the polymer contained in the elementary body, and heating the elementary body under an inert gas atmosphere, After the inert firing step of reacting the polymer to form a matrix, the oxygen supply step and the inert firing step, the element body is heated in an oxygen atmosphere to remove the interface layer, An oxygen firing step to produce a ceramic-based composite material in which the matrix is arranged between the fibers.

It is preferable that the inert firing step is performed after the oxygen supply step.

In the oxygen supply step, by heating the element body in an oxygen atmosphere, oxygen is supplied to the polymer, and the heating temperature of the element body in the oxygen supply step is the inert firing step and the oxygen firing step. It is preferable that the heating temperature is lower than the heating temperature.

The heating temperature of the element body in the oxygen supply step is preferably 200° C. or higher and lower than 600° C.

In the oxygen supply step, by holding the element body in a steam atmosphere, oxygen is supplied to the polymer, and the temperature of the steam in the oxygen supply step is the same in the inert firing step and the oxygen firing step. It is preferably lower than the heating temperature.

The temperature of the water vapor in the oxygen supplying step is preferably 80° C. or higher and lower than 200° C.

It is preferable that the polymer includes ceramics made of the same material as the fibers.

The interface layer is preferably a layer containing carbon as a main component.

According to the present invention, it is possible to suppress the strength reduction of the ceramic matrix composite material.

FIG. 1 is a block diagram of a manufacturing system according to this embodiment. FIG. 2 is a schematic diagram showing the configuration of the element body according to the present embodiment. FIG. 3 is a schematic enlarged view of a cross section of the element body according to the present embodiment. FIG. 4 is a schematic enlarged view of a cross section of the element body according to the present embodiment. FIG. 5 is a flowchart showing the method for manufacturing the ceramic-based composite material according to this embodiment. FIG. 6 is a schematic diagram showing changes in each layer due to the manufacturing process of the ceramic matrix composite material. FIG. 7 is a diagram showing a chemical formula showing an example of modification of a resin. FIG. 8 is a schematic view showing the structure of the ceramic matrix composite material according to this embodiment. FIG. 9 is a schematic enlarged view of a cross section of the ceramic-based composite material according to this embodiment. FIG. 10 is a graph showing the measurement results of bending strength.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the present invention is not limited to this embodiment, and when there are a plurality of embodiments, the present invention also includes those configured by combining the respective embodiments.

FIG. 1 is a block diagram of a manufacturing system according to this embodiment. The manufacturing system 1 according to the present embodiment is a system for manufacturing the ceramic-based composite material 102 by processing the element body 100 by the PIP method (Polymer Ignition and Pyrolysis method), and the ceramic-based composite material according to the present embodiment. This is a system for implementing the manufacturing method of 102. As shown in FIG. 1, the manufacturing system 1 includes an element body forming device 2, an oxygen supply device 4, an inert firing device 6, and an atmospheric firing device 8. The element body forming device 2 is an apparatus that forms the element body 100 by performing an impregnation step described later. The oxygen supply device 4 is a device that performs an oxygen supply step described below, the inert firing device 6 is a device that performs an inert firing step described below, and the atmospheric firing device 8 performs an oxygen firing step described below. This is an apparatus that is executed to generate the ceramic matrix composite material 102. The element body forming device 2, the oxygen supply device 4, the inert calcination device 6, and the atmospheric calcination device 8 may have any structures as long as they can perform the respective steps.

The ceramic-based composite material 102 is a CMC (Ceramic Matrix Composites) member. The ceramic-based composite material 102 is a member in which the matrix 30B is arranged between the ceramic fibers 24, and is manufactured by processing the element body 100.

First, the configuration of the element body 100 will be described. FIG. 2 is a schematic diagram showing the configuration of the element body according to the present embodiment. 3 and 4 are schematic enlarged views of the cross section of the element body according to the present embodiment. As shown in FIG. 2, the element body 100 is formed into a thin plate shape by laminating a plurality of fiber layers 10 as an example. In other words, the element body 100 has a plurality of fiber layers 10 arranged in an overlapping manner. In the example shown in FIG. 2, a boundary line is displayed between the plurality of fiber layers 10 for convenience, but in the actual element body 100, such a clear boundary line is formed between the fiber layers 10. Does not exist, and the plurality of fiber layers 10 are integrated with each other. Further, the shape of the element body 100 is not limited to the plate shape shown in FIG. 2 and can be various shapes.

FIG. 3 schematically shows the configuration of the fiber layer 10. As shown in FIG. 3, the fiber layer 10 includes a woven fabric 20 and a polymer 30. The woven cloth 20 is a woven fabric of the fiber bundle 22, that is, a woven fabric formed by weaving the fiber bundle 22. The woven fabric 20 can be formed by applying plain weave or satin weave to the fiber bundle 22. Furthermore, the woven fabric 20 can be formed as a non-woven fabric using the fiber bundle 22.

The fiber bundle 22 has a plurality of fibers 24, and the plurality of fibers 24 are configured in a bundle. The fiber 24 is a fiber containing ceramics as a main component, that is, a fiber made of ceramics. Furthermore, in this embodiment, the fiber 24 is mainly composed of oxide ceramics, and examples of the oxide ceramics include alumina and mullite. Further, the fibers 24 may be SiC fibers.

As shown in FIG. 4, an interface layer 26 is provided around the fibers 24. The interface layer 26 is a layer formed of a material different from the fiber 24 and the polymer 30. In the present embodiment, the interface layer 26 is a layer containing carbon as a main component, and has a carbon-based composition such as CNO in the present embodiment. As described above, since the interface layer 26 is provided around each fiber 24, the woven fabric 20 (or the fiber bundle 22) includes the plurality of fibers 24 and the interface layer 26 that surrounds the fibers 24. Can be said to have.

The polymer 30 is arranged in a gap formed between the plurality of fiber bundles 22 or a gap between the fibers 24. Since the interface layer 26 is provided around the fibers 24, it can be said that the polymer 30 is arranged between the fibers 24 via the interface layer 26. The polymer 30 is a precursor of the matrix 30B described later. That is, the matrix 30B is formed by the reaction of the polymer 30. Furthermore, the polymer 30 is in the form of a fluid slurry and is hardened by thermal decomposition in an inert firing step and an oxygen firing step, which will be described later, to form the matrix 30B. Furthermore, the polymer 30 is a precursor of oxide-based ceramics. The polymer 30 is a precursor of the same ceramic as the fiber 24, that is, an oxide ceramic such as alumina and mullite, and contains metalloxane (M—O bond) such as Al—O bond and Si—O bond.

The element body 100 is configured as described above. In the present embodiment, the ceramic matrix composite material 102 is manufactured by processing the element body 100. Hereinafter, a method for manufacturing the ceramic matrix composite material 102 will be described.

FIG. 5 is a flowchart showing the method for manufacturing the ceramic-based composite material according to this embodiment. FIG. 6 is a schematic diagram showing changes in each layer due to the manufacturing process of the ceramic matrix composite material. As shown in FIG. 5, in the manufacturing method according to the present embodiment, first, a cutting step S10 is executed. In the cutting step S10, the woven cloth 20 is cut into a predetermined desired shape and size.

In the manufacturing method according to the present embodiment, next, an interface layer forming step S12 is executed. In the interface layer forming step S12, the interface layer 26 is formed around the fibers 24 of the cut woven fabric 20. In this embodiment, the resin is attached in advance around the fibers 24. The resin here is, for example, a polyurethane polymer. Then, the cut woven fabric 20 is heated in an inert gas atmosphere to cause a chemical reaction in the resin, and the resin is modified into the interface layer 26. FIG. 7 is a diagram showing a chemical formula showing an example of modification of a resin. As shown in FIG. 7, when polyurethane is used as the resin, by heating in an inert gas atmosphere, CNO as the interface layer 26 is generated through the synthesis and thermal decomposition of polyurethane. The inert gas here is nitrogen, but it is not limited to nitrogen and may be, for example, argon.

The resin attached around the fibers 24 is not limited to the polyurethane resin. The resin attached to the periphery of the fiber 24 includes polyurethane resin, epoxy resin, polybutadiene, polyalkylene glycol, polyolefin resin, vinyl ester resin, saturated polyester resin, unsaturated polyester resin, polyamide resin, polyimide resin, polyamideimide resin, At least one selected from the group of acrylic resin, polypropylene resin, and pitch-based resin may be used. In other words, if at least one chemical species of the above group is contained as a resin, the interface layer 26 can be easily formed by heating in an inert gas atmosphere.

In the manufacturing method according to the present embodiment, the interface layer 26 is formed from the resin attached around the fibers 24 by heating the woven fabric 20 attached with the resin in the inert gas atmosphere as described above. The method of forming the interface layer 26 is not limited to this, and is arbitrary. For example, the interface layer 26 may be directly bonded to the periphery of the fiber 24 without using a resin, or as direct bonding, for example, vapor deposition may be performed.

As shown in FIG. 5, in the manufacturing method according to the present embodiment, the stacking step S14 is performed after the interface layer forming step S12. In the laminating step S14, a plurality of woven fabrics 20 are laminated until a desired thickness is obtained. When laminating the woven fabric 20, the laminated woven fabric 20 can be made to have pseudo isotropicity by changing the major axis direction of the fibers for each layer. Specifically, when n layers of woven fabric 20 are laminated, pseudo isotropicity can be realized by changing the major axis direction of the fibers of each layer by (360/n)°.

In the manufacturing method according to the present embodiment, the impregnation step S16 is performed after the stacking step S14 is performed. In the impregnation step S16, the woven fabric 20 is impregnated with the polymer 30 to form the element body 100. In the present embodiment, the woven cloth 20 is dipped in the slurry-like polymer 30 to fill the space between the fibers 24 with the polymer 30. As a result, the element body 100 in which the woven fabric 20 is impregnated with the polymer 30 is formed. As described above, in the present embodiment, the impregnation step S16 is performed after the woven fabric 20 is laminated in the lamination step S14. That is, in the present embodiment, the laminated body of the woven cloth 20 is impregnated with the polymer 30 to form the element body 100 that is the laminated body of the fiber layers 10. However, the order of the stacking step S14 and the impregnation step S16 is arbitrary. For example, the impregnation step S16 is first performed to form the fiber layer 10 that is the woven fabric 20 impregnated with the polymer 30, and then the lamination step S14 is performed to laminate the fiber layer 10. The element body 100 may be formed.

By performing the stacking step S14 and the impregnation step S16, the element body 100 is formed. The impregnation step S16 is performed by the element body forming device 2. The element body forming device 2 may execute a series of processes from the cutting step S10 to the impregnation step S16, or may execute only the impregnation step S16. Further, the impregnation step S16 may be performed manually by an operator.

When the element body 100 is formed by the impregnation step S16, the element body 100 is processed to manufacture the ceramic matrix composite material 102. Specifically, in the manufacturing method according to the present embodiment, the oxygen supply step S18 is performed after the impregnation step S16. In the oxygen supply step S18, oxygen is supplied to the polymer 30 contained in the element body 100, that is, the polymer 30 impregnated in the woven fabric 20. That is, as shown in FIG. 6, oxygen is introduced into the polymer 30 of the element body 100 formed in the impregnation step S16 in the oxygen supply step S18, so that the polymer 30 contains oxygen. That is, in the oxygen supply step S18, it can be said that the polymer 30 of the element body 100 is oxidized. As shown in FIG. 6, hereinafter, the polymer 30 containing oxygen in the oxygen supply step S18 will be referred to as a polymer 30A. It can be said that the polymer 30A is a member in which the polymer 30 is oxidized. Further, the element body 100 after the execution of the oxygen supply step S18, that is, the element body 100 including the polymer 30A is referred to as an element body 100A. The element body 100A is different from the element body 100 in that the polymer is oxidized. However, the fibers 24 and the interface layer 26 included in the element body 100A do not react with each other, and have the same chemical composition as the fibers 24 and the interface layer 26 included in the element body 100.

In the oxygen supply step S18 of the present embodiment, the element body 100 is heated at the first temperature in an oxygen atmosphere to supply oxygen to the polymer 30 (oxidize the polymer 30) to generate the polymer 30A. .. The oxygen atmosphere refers to an atmosphere of a gas containing oxygen, and in the present embodiment, it is an air atmosphere. However, in the oxygen supply step S18, the element body 100 may be heated, for example, in an atmosphere of a gas containing only oxygen.

The first temperature, which is the heating temperature of the element body 100 in the oxygen supply step S18, is lower than the heating temperature (second heating temperature) in the inert firing step S20, which will be described later, and the heating temperature in the oxygen firing step S22, which will be described later (third heating). Temperature)). The first temperature is low enough to suppress the oxidation of the interface layer 26, but is preferably high enough to activate the oxidation of the polymer 30. Specifically, the first temperature is preferably 200° C. or higher and lower than 600° C., and more preferably 400° C. or higher and 500° C. or lower. By heating the element body 100 in such a relatively low temperature range, it is possible to favorably suppress the oxidation of the interface layer 26 while favorably promoting the oxidation of the polymer 30.

In the oxygen supply step S18, the element body 100 is heated at the first temperature in the oxygen atmosphere for 5 minutes or more. In addition, in the oxygen supply step S18, it is preferable to heat the element body 100 at the first temperature in the oxygen atmosphere for 180 minutes or less. However, the implementation time of the oxygen supply step S18 is not limited to this.

The oxygen supply step S18 described above is performed by the oxygen supply device 4. The oxygen supply device 4 is, for example, a heating furnace, holds the element body 100 inside, and heats the inside to a first temperature in an oxygen atmosphere to execute the oxygen supply step S18.

As described above, the oxygen supply step S18 heats the element body 100 at the first temperature in an oxygen atmosphere, but is a step capable of supplying oxygen to the polymer 30 (oxidizing the polymer 30). If so, the content of the process is arbitrary. For example, in the oxygen supply step S18, oxygen may be supplied to the polymer 30 by holding the element body 100 in a steam atmosphere at a predetermined temperature for a predetermined time. The predetermined temperature here is preferably 80° C. or higher and 200° C. or lower. By holding the element body 100 in a water vapor atmosphere at such a temperature, it is possible to suitably suppress the oxidation of the interface layer 26 and appropriately accelerate the oxidation of the polymer 30. Further, the predetermined time here is, for example, 1 hour or longer and the predetermined time is preferably 180 minutes or shorter, but is not limited thereto and is arbitrary.

In the manufacturing method according to the present embodiment, the inert firing step S20 is performed after the oxygen supply step S18. In the inert firing step S20, the base body 100A is heated in an inert gas atmosphere to react the polymer 30A and form the matrix 30B. More specifically, as shown in FIG. 6, by heating the element body 100A in an inert gas atmosphere in the inert firing step S20, the oxidation of the interface layer 26 is suppressed and the interface layer 26 is left while the polymer 30A is kept. Are reacted to generate a matrix 30B. The inert gas atmosphere refers to an inert gas atmosphere, and in the present embodiment, a nitrogen atmosphere. However, the inert gas is not limited to nitrogen, and may be, for example, argon. The inert gas atmosphere is preferably a non-oxygen atmosphere, that is, a gas atmosphere containing no oxygen.

Specifically, the polymer 30A is heated in the inert baking step S20, whereby a dehydration reaction occurs, the OH group contained in the polymer 30A becomes an oxo group (O group), and the polymer 30A as a precursor is a matrix. It becomes 30B. Therefore, in the matrix 30B after the inert baking step S20, intermolecular condensation occurs between adjacent oxo groups. Further, in the matrix 30B, intramolecular condensation due to the oxo group also occurs. The matrix 30B is a solidified body of the same ceramic as the fiber 24, that is, an oxide ceramic such as alumina and mullite. The reaction of modifying the polymer 30A into the matrix 30B is not completed in the inert firing step S20 and continues in the oxygen firing step S22 described later.

In the inert firing step S20, the element body 100A is heated at the second temperature in an inert gas atmosphere. The second temperature is higher than the first temperature in the oxygen supply step S18, as described above. The second temperature is a temperature that is high enough to react the polymer 30A, and is preferably 800° C. or higher and 1300° C. or lower. In addition, in the inert firing step S20, heating of the element body 100A at the second temperature in an inert gas atmosphere is performed for 5 minutes or more. In addition, in the inert firing step S20, it is preferable that heating of the element body 100A at the second temperature in an inert gas atmosphere is performed for 180 minutes or less. However, the execution time of the inert firing step S20 is not limited to this.

As described above, in the inert firing step S20, the element body 100A is heated at the second temperature in the inert gas atmosphere, so that the formation of the matrix 30B is promoted and the oxidation of the interface layer 26 is suppressed. .. That is, the oxidation of the interface layer 26 is suppressed because of the inert gas atmosphere, and the contact between the polymer 30A and the fiber 24 during the reaction is suppressed by the interface layer 26. Hereinafter, the element body 100A after the execution of the inert firing step S20, that is, the element body 100A including the matrix 30B is referred to as an element body 100B. The element body 100B is different from the element body 100A in that a part of the polymer 30A is modified into the matrix 30B. However, the fibers 24 and the interface layer 26 included in the element body 100B have no reaction, and have the same chemical composition as the fibers 24 and the interface layer 26 included in the element body 100A.

The inert firing step S20 is performed by the inert firing device 6. The inert firing device 6 is, for example, a heating furnace, holds the element body 100A inside, and heats the inside to a second temperature in an inert gas atmosphere, thereby executing the inert firing step S20. The inert firing device 6 may be the same device as the oxygen supply device 4 when the internal atmosphere can be adjusted.

In the present embodiment, the inert firing step S20 is performed after the oxygen supply step S18, but the present invention is not limited to this, and the oxygen supply step S18 may be performed after the inert firing step S20. That is, the oxygen supply step S18 and the inert firing step S20 may be performed in any order as long as they are performed before the oxygen firing step S22 described later. Even if the oxygen supply step S18 is performed after the inert firing step S20, it is possible to supply oxygen to the polymer 30 while suppressing the oxidation of the interface layer 26 by the time the oxygen firing step S22 is performed. ..

Further, in the present embodiment, the oxygen supply step S18 and the inert firing step S20 may be executed multiple times. For example, after the oxygen supply step S18, the process may return to the impregnation step S16 to further impregnate the polymer 30, and then the oxygen supply step S18 may be executed again to supply oxygen to the polymer 30. That is, the impregnation step S16 and the oxygen supply step S18 may be repeated a plurality of times. Alternatively, after the inert firing step S20, the process may return to the impregnation step S16 to further impregnate the polymer 30, and then the oxygen supply step S18 and the inert firing step S20 may be performed again. That is, the impregnation step S16, the oxygen supply step S18, and the inert firing step S20 may be repeated a plurality of times. By thus repeating the steps a plurality of times, the dense ceramic matrix composite material 102 can be manufactured.

In the manufacturing method according to the present embodiment, the oxygen firing step S22 is performed after the inert firing step S20. In the oxygen firing step S22, the element body 100B is heated in an oxygen atmosphere to remove the interface layer 26 by oxidation and react the polymer 30A to generate the matrix 30B, as shown in FIG. The ceramic matrix composite material 102 is formed from the element body 100B. In the inert baking step S20, a part of the polymer 30A is modified into the matrix 30B. In the oxygen firing step S22, the polymer 30A is modified into the matrix 30B following the inert firing step S20. In other words, the remaining polymer 30A is modified into the matrix 30B and the modification treatment into the matrix 30B is completed. .. The oxygen atmosphere means an atmosphere of a gas containing oxygen, and in the present embodiment, it is an air atmosphere. However, the oxygen supply step S18 may be performed, for example, in a gas atmosphere containing only oxygen.

In the oxygen firing step S22, the element body 100B is heated at a third temperature in an oxygen atmosphere. As described above, the third temperature is higher than the first temperature in the oxygen supply step S18. The third temperature is a temperature high enough to react the polymer 30A and decompose the interface layer 26, and is preferably 800° C. or higher and 1300° C. or lower. That is, the third temperature is preferably the same temperature as the second temperature. In the oxygen firing step S22, heating the element body 100B at the third temperature in an oxygen atmosphere is performed for 5 minutes or more. Further, in the oxygen firing step S22, it is preferable that the element body 100B is heated at the third temperature in an oxygen atmosphere for 300 minutes or less. However, the execution time of the oxygen firing step S22 is not limited to this.

The interface layer 26 is oxidized and vaporized by being heated at the third temperature in the oxygen atmosphere. That is, in the oxygen firing step S22, by heating the element body 100B at a high temperature in the oxygen atmosphere in this way, as shown in FIG. 6, while oxidizing the interface layer 26, the polymer 30A is reacted to form the matrix 30B. Then, the ceramic matrix composite material 102 is generated from the element body 100B. The ceramic-based composite material 102 has a structure in which the matrix 30B is arranged (filled) around the woven cloth 20, that is, the fibers 24, and does not include the interface layer 26. Since the interface layer 26 is vaporized and removed by oxidation, in the ceramic-based composite material 102, the space where the interface layer 26 was present, that is, the space around the fiber 24 becomes the void V that is not filled with the matrix 30B. Since the ceramic-based composite material 102 includes the pores V, the reduction in brittleness can be suppressed.

The reaction of modifying the polymer 30A into the matrix 30B may be completed in the inert firing step S20, and may not occur in the oxygen firing step S22. In this case, the oxygen firing step S22 only removes the interface layer 26.

This oxygen firing step S22 is performed by the atmospheric firing device 8. The atmospheric calcination device 8 is, for example, a heating furnace, holds the element body 100B inside, and heats the inside to a third temperature in an oxygen atmosphere to execute the oxygen calcination step S22. The atmospheric firing device 8 may be the same device as the oxygen supply device 4.

FIG. 8 is a schematic view showing the structure of the ceramics-based composite material according to the present embodiment, and FIG. 9 is a schematic enlarged view of a cross section of the ceramics-based composite material according to the present embodiment. Since the ceramic-based composite material 102 is manufactured from the element body 100 through the above steps, as shown in FIG. 8, it is a member in which the fiber layers 10 a are laminated, as in the element body 100. In the example shown in FIG. 8, a boundary line is displayed between the plurality of fiber layers 10a for the sake of convenience. However, in the actual ceramic-based composite material 102, such a clear line is formed between the fiber layers 10a. There is no boundary line, and the plurality of fiber layers 10a are integrated with each other. As shown in FIG. 9, the fiber layer 10a includes a woven fabric 20 and a matrix 30B. As shown in FIG. 9, the fiber layer 10 a is the same as the fiber layer 10 of the element body 100 shown in FIG. 3 in that the woven fabric 20 is obtained by weaving a fiber bundle 22 having a plurality of fibers 24. Is. However, as shown in S22 of FIG. 6, the fiber layer 10a is different from the fiber layer 10 of the element body 100 in that the interface layer 26 is not included around the fiber 24 and the polymer 30A is the matrix 30B. ..

As described above, the method for manufacturing the ceramic-based composite material 102 according to this embodiment includes the impregnation step S16, the oxygen supply step S18, the inert firing step S20, and the oxygen firing step S22. In the impregnation step S16, the woven fabric 20 having the plurality of ceramic fibers 24 and the interface layer 26 covering the fibers 24 is impregnated with the polymer 30 as the precursor to form the element body 100. In the oxygen supply step S18, oxygen is supplied to the polymer 30 contained in the element body 100. In the inert calcination step S20, the matrix (polymer 30A in this embodiment) is reacted by heating the matrix (element 100A in this embodiment) in an inert gas atmosphere to form the matrix 30B. In the oxygen firing step S22, after the oxygen supply step S18 and the inert firing step S20, the element body 100B is heated in an oxygen atmosphere to remove the interface layer 26 and the matrix 30B is formed between the fibers 24. The ceramic matrix composite material 102 to be arranged is generated.

Here, when a ceramic-based composite material is manufactured by firing an element body in which a woven fabric is impregnated with a polymer, the fibers in the woven fabric are deteriorated due to contact with the polymer in the firing reaction, and The strength of the base composite material may decrease. Therefore, in order to suppress the contact between the fiber and the polymer, an interface layer may be provided around the fiber. However, when the element body provided with the interface layer is fired in the air atmosphere, the interface layer is decomposed during firing, and eventually the fiber and the polymer come into contact with each other, so that reduction in strength cannot be suppressed. On the other hand, in order to prevent the decomposition of the interface layer, first the element body is fired in a nitrogen atmosphere to cause the reaction of the polymer while maintaining the interface layer, and then it is fired in the air to promote the reaction of the polymer and the interface layer. Can also be removed. In this case, since the element body is fired in a nitrogen atmosphere, the polymer can be used as a matrix while leaving the interface layer, and the contact between the fiber and the polymer can be suppressed. Then, after the formation of the matrix has progressed to some extent by firing in a nitrogen atmosphere, air firing can be performed to remove the interface layer. However, since firing is carried out in a nitrogen atmosphere, oxygen for reacting with the polymer is insufficient, and firing failure of the matrix may occur. In this case also, the strength of the ceramic matrix composite material decreases.

On the other hand, in the method for manufacturing the ceramic-based composite material 102 according to the present embodiment, the oxygen supply step S18 is performed before the oxygen firing step S22 to sufficiently supply oxygen to the polymer 30 and perform the inert firing step. By executing S20, the generation of the matrix 30B from the polymer 30 proceeds while the interface layer 26 remains. Then, by performing the oxygen firing step S22 after that, the interface layer 26 can be removed while firing the polymer 30 while the polymer 30 sufficiently contains oxygen. Therefore, according to the manufacturing method of the present embodiment, it is possible to suppress contact between the fiber 30 and the polymer 30 during firing and suppress firing failure of the matrix 30B, and thus suppress deterioration of strength of the ceramic matrix composite material 102. be able to.

Further, in the manufacturing method according to the present embodiment, the inert firing step S20 is performed after the oxygen supply step S18. Since the oxygen supply step S18 is performed first, it is possible to perform the firing of the polymer 30A in the inert firing step S20 while sufficiently supplying oxygen to the polymer 30, and it is possible to more appropriately suppress the firing failure of the matrix 30B. You can

Further, in the manufacturing method according to the present embodiment, in the oxygen supply step S18, oxygen is supplied to the polymer 30 by heating the element body 100 in an oxygen atmosphere. The heating temperature (first temperature) of the element body 100 in the oxygen supply step S18 is lower than the heating temperatures (second temperature and third temperature) in the inert firing step S20 and the oxygen firing step S22. In the manufacturing method according to the present embodiment, since the element body 100 is heated at a low temperature in an oxygen atmosphere, oxygen can be supplied to the polymer 30 while suppressing the reaction of the polymer 30 and the removal of the interface layer 26. Therefore, according to this manufacturing method, it is possible to suppress a decrease in strength of the ceramic-based composite material 102.

The heating temperature of the element body 100 in the oxygen supply step S18 is 200°C or higher and lower than 600°C. According to this manufacturing method, since the element body 100 is heated in this temperature range, oxygen can be supplied to the polymer 30 while suppressing the reaction of the polymer 30 and the removal of the interface layer 26. Therefore, according to this manufacturing method, it is possible to suppress a decrease in strength of the ceramic-based composite material 102.

Further, in the oxygen supply step S18, oxygen may be supplied to the polymer 30 by holding the element body 100 in a water vapor atmosphere. The temperature of the water vapor in the oxygen supply step S18 is lower than the heating temperature (second temperature and third temperature) in the inert firing step S20 and the oxygen firing step S22. Since the manufacturing method according to the present embodiment holds the element body 100 in a water vapor atmosphere, oxygen can be supplied to the polymer 30 while suppressing the reaction of the polymer 30 and the removal of the interface layer 26. Therefore, according to this manufacturing method, it is possible to suppress a decrease in strength of the ceramic-based composite material 102.

Further, the temperature of the steam in the oxygen supply step S18 is 80° C. or higher and lower than 200° C. According to this manufacturing method, since the element body 100 is held in this temperature range, oxygen can be supplied to the polymer 30 while suppressing firing of the polymer 30 and removal of the interface layer 26. Therefore, according to this manufacturing method, it is possible to suppress a decrease in strength of the ceramic-based composite material 102.

Further, the polymer 30 includes ceramics made of the same material as the fiber 24. By using such a polymer 30, the ceramic-based composite material 102 can be preferably manufactured.

The interface layer 26 is a layer containing carbon as a main component. By using such an interface layer 26, it is possible to suppress the contact between the fiber 24 and the polymer 30 and suppress the strength reduction of the ceramic matrix composite material 102.

(Example)
Next, an example of this embodiment will be described. In the example, the ceramic matrix composite material 102 was manufactured from the element body 100 by the method shown in FIG. Further, as Comparative Example 1, the ceramic base composite material 102X1 was manufactured by firing the element body 100 in an air atmosphere in a temperature range of 800° C. or higher and 1300° C. or lower. Further, as Comparative Example 2, after firing the element body 100 in a nitrogen atmosphere in a temperature range of 800° C. or higher and 1300° C. or lower, further firing in an air atmosphere in a temperature range of 800° C. or higher and 1300° C. or lower, A ceramic matrix composite material 102X2 was manufactured. Then, the bending strength of the ceramic-based composite material 102 according to the example, the ceramic-based composite material 102X1 according to the comparative example 1, and the ceramic-based composite material 102X2 according to the comparative example 2 were measured.

FIG. 10 is a graph showing the measurement results of bending strength. As shown in FIG. 10, when the bending strength of the ceramic-based composite material 102X1 according to Comparative Example 1 is set to 1, the bending strength of the ceramic-based composite material 102X2 according to Comparative Example 2 is about 1.2. Further, the bending strength of the ceramic matrix composite material 102 according to the example is about 1.7. Thus, it is understood that when the ceramic-based composite material 102 is manufactured as in the example, the decrease in bending strength is suppressed.

Although the embodiment of the present invention has been described above, the embodiment is not limited by the contents of this embodiment. Further, the above-described constituent elements include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those that are in a so-called equivalent range. Furthermore, the components described above can be combined appropriately. Furthermore, various omissions, substitutions, or changes of the constituent elements can be made without departing from the scope of the above-described embodiment.

1 Manufacturing System 10 Fiber Layer 20 Woven Fabric 24 Fiber 26 Interface Layer 30, 30A Polymer 30B Matrix 100 Element Body 102 Ceramic Matrix Composite Material

Claims (8)

An impregnating step of impregnating a woven fabric having a plurality of fibers made of ceramics and an interface layer covering the periphery of the fibers with a polymer as a precursor to form an element body;
An oxygen supply step of supplying oxygen to the polymer contained in the element body,
By heating the element body under an inert gas atmosphere, an inert firing step of reacting the polymer to form a matrix,
A ceramic matrix composite material in which the interface layer is removed by heating the element body in an oxygen atmosphere after the oxygen supply step and the inert firing step, and the matrix is arranged between the fibers. An oxygen firing step to produce
A method for producing a ceramic-based composite material, comprising: The method for producing a ceramics-based composite material according to claim 1, wherein the inert firing step is performed after the oxygen supply step. In the oxygen supply step, by heating the element body under an oxygen atmosphere, oxygen is supplied to the polymer,
The method for manufacturing a ceramic matrix composite material according to claim 1 or 2, wherein a heating temperature of the element body in the oxygen supply step is lower than heating temperatures in the inert firing step and the oxygen firing step. The method for producing a ceramic-based composite material according to claim 3, wherein a heating temperature of the element body in the oxygen supply step is 200° C. or higher and lower than 600° C. 5. In the oxygen supply step, by holding the element body under a water vapor atmosphere, oxygen is supplied to the polymer,
The method for producing a ceramics-based composite material according to claim 1 or 2, wherein the temperature of the water vapor in the oxygen supply step is lower than the heating temperatures in the inert firing step and the oxygen firing step. The method for producing a ceramics-based composite material according to claim 5, wherein the temperature of the water vapor in the oxygen supply step is 80° C. or higher and lower than 200° C. 6. The method for producing a ceramics-based composite material according to claim 1, wherein the polymer contains ceramics which is the same material as the fiber. The method for manufacturing a ceramics-based composite material according to claim 1, wherein the interface layer is a layer containing carbon as a main component.

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