JP6888949B2 - Method for manufacturing SiC fiber reinforced SiC composite material - Google Patents

Description

The present invention relates to a method for producing a SiC fiber reinforced SiC composite material.

Since ceramic composites have heat resistance, oxidation resistance, damage tolerance, etc., they are expected to be used in fields with severe usage environments such as the energy industry, aerospace, and non-ferrous / metal fields. Among them, a silicon carbide fiber-reinforced silicon carbide composite material (hereinafter referred to as SiC fiber-reinforced SiC composite material) using silicon carbide fiber (hereinafter referred to as SiC fiber) as a reinforcing fiber and silicon carbide as a matrix is expected to have excellent characteristics. It is increasing.

The SiC fiber-reinforced SiC composite material forms an interface layer made of foreign substances such as BN and thermally decomposed carbon between the strands of SiC fiber, which is an aggregate, and the SiC matrix, and integrates the SiC fiber and the SiC matrix. It prevents it and demonstrates its characteristics as a composite material. As the SiC fiber reinforced SiC composite material, there are various forms of SiC fiber reinforced SiC composite material such as a cloth woven with strands of SiC fibers, which is an aggregate, and a wound filament winding, and various shapes can be used. Can be formed.

Patent Document 1 describes a method for manufacturing a polygonal tubular body, in which a ceramic fiber is wound around a polygonal mandrel having an R-plane shape portion on a longitudinal side, and a plurality of layers having different winding angles with respect to the axis of the mandrel. A winding step of obtaining a wound body in which ceramic fiber layers are laminated, a CVD step of coating the wound body with ceramic-CVD to form a coating body, and a mandrel removing step of removing mandrel from the coating body. The ceramic fiber layer is made of a ceramic / ceramic composite material, wherein the outermost ceramic fiber layer has a smaller winding angle with respect to the axis of the mandrel than the ceramic fiber layer immediately below the outermost ceramic fiber layer. A method for producing a polygonal tubular body is described.

By arranging the SiC fiber layer having a small winding angle with respect to the axis of the mandrel in the outermost layer in this way, the bending method of the outermost layer SiC fiber can be made gentle and it can be made difficult to break. That is, the SiC fiber layer that easily fluffs can be covered with the SiC fiber layer that does not easily fluff, and the occurrence of fluffing can be suppressed.

Japanese Unexamined Patent Publication No. 2016-13950

However, since SiC fibers are originally brittle materials, they are cut when a force is locally applied. When a small-diameter pipe or the like is formed by using a strand which is a bundle of SiC fibers, the SiC fibers are broken due to the brittleness of the SiC, and fluffing is likely to occur. When fluffing occurs, it causes a decrease in strength. In addition, when a matrix is formed by the CVD method in the process of forming a SiC fiber-reinforced SiC composite material, the matrix grows on the fluffed SiC fiber and becomes a source of defects. ..

In view of the above problems, an object of the present invention is to provide a method for producing a SiC fiber-reinforced SiC composite material, which is less likely to cause fluffing even when the SiC fiber is bent with a small radius of curvature.

The method for producing a SiC fiber-reinforced SiC composite material of the present invention for solving the above problems is
(1) A base material forming step of forming a base material using strands composed of a plurality of carbon fibers and a sizing agent, a sizing agent removing step of removing the sizing agent from the base material, and removing the sizing agent . A SiC coating forming step of putting the base material into a CVD furnace and forming a SiC coating on the surface with the carbon fiber as a core, an interface layer forming step of forming an interface layer on the outside of the SiC coating, and an outside of the interface layer. Includes a matrix forming step of forming a SiC matrix.

In the method for producing a SiC fiber-reinforced SiC composite material of the present invention, a base material is formed using strands composed of carbon fibers and a sizing agent. Since carbon has a hexagonal crystal structure in which the c-axis direction is bonded by a van der Waals force, it has a lubricating action and it is difficult to apply a strong force to the carbon fibers. Even if the base material is formed in the form of a cloth or the like, the base material is formed at the stage of carbon fibers in which a strong frictional force is unlikely to be generated on the surface, so that the occurrence of fluffing can be reduced. Further, since the strand has a sizing agent, the friction between the fibers is further reduced, making it difficult to cut.

In the method for producing a SiC fiber-reinforced SiC composite material of the present invention, the aggregate is formed by weaving and winding at the stage of carbon fiber. Therefore, at the stage of forming the aggregate, the surface is coated with ceramic as an interface layer. There is no. Therefore, the ceramic coating on the surface is not peeled off and the ceramic fibers are not damaged, and fluffing can be less likely to occur.

The method for producing a SiC fiber-reinforced SiC composite material of the present invention preferably has the following aspects.

(2) The base material forming step comprises at least one of a weaving method of weaving a cloth, a braiding method of knitting a braid body, and a filament winding method of winding a filament winding body.

In the weaving method, the braiding method, and the filament winding method, continuous SiC fibers are combined to form an aggregate with bending. Therefore, when the fibers are cut and fluffing occurs, gaps are formed in the SiC fibers, making it difficult for the SiC matrix to completely fill the gaps, and defects are likely to occur in the SiC matrix. In the method for producing a SiC fiber-reinforced SiC composite material of the present invention, cutting is unlikely to occur even at a bent portion of the SiC fiber, so that the SiC matrix is easily filled between the aggregates to obtain a strong SiC fiber-reinforced SiC composite material. Can be done.

(3) The sizing agent removing step is either a cleaning method or a heating method.

Examples of the sizing agent include epoxy resins, polypropylenes, polyethylenes, vinyl ester resins, silicone resins, hydrazide resins, polyethylene oxides and the like. By removing these sizing agents, SiC can be formed directly on the carbon fibers. The method for removing the sizing agent can be appropriately selected depending on the type of the sizing agent. A water-soluble sizing agent can be washed with water, and a sizing agent soluble in an organic solvent can be washed with an organic solvent. Further, any sizing agent that can be heated to a temperature equal to or higher than the boiling point and sublimation point, and a sizing agent that is thermally decomposed so that no residue remains can be removed by heating, evaporation, sublimation, or thermal decomposition.

Further, in the method for producing a SiC fiber-reinforced SiC composite material of the present invention, after forming a base material using a plurality of carbon fibers, the sizing agent is removed, a SiC coating is formed on the carbon fibers, and the SiC fibers are obtained. There is. Since the SiC fiber obtained in the present invention is obtained by the CVD method, it does not contain oxygen like the SiC fiber obtained by spinning the precursor. When oxygen is contained, it reacts with SiC at a high temperature, decomposes into gases such as SiO and CO, and becomes a source of forming defects in SiC fibers. Since the SiC fiber of the present invention has CVD-SiC formed in the core of the carbon fiber, it is possible to obtain a SiC fiber-reinforced SiC composite material that does not contain oxygen and has high heat resistance.

In the method for producing a SiC fiber-reinforced SiC composite material of the present invention, an interface layer is formed on the surface of the obtained SiC fiber. The interface layer prevents the SiC fiber from being integrated with the SiC matrix after the SiC fiber-reinforced SiC composite material is formed, and acts so that the SiC fiber is pulled out from the matrix, so that the performance as a composite material is exhibited. Will be able to.

The method for producing a SiC fiber-reinforced SiC composite material of the present invention further includes a matrix forming step of forming a SiC matrix on the outside of the interface layer. In the matrix forming step, a CVD method in which the raw material gas is deposited between the SiC fibers of the aggregate, a precursor method in which the aggregate is impregnated with the resin of the precursor and then thermally decomposed can be used.

(4) The interface layer is made of BN or pyrolytic carbon.

The BN or pyrolytic carbon, which is the interface layer, is a hexagonal crystal and is bonded by van der Waals force in the c-axis direction, so that it has a crystal structure that is easily cleaved. Therefore, when the interface layer is made of these ceramics, the matrix and the SiC fiber which is the aggregate are prevented from being integrated, and the SiC fiber acts so as to be pulled out from the matrix. You will be able to demonstrate its performance.

(5) The matrix forming step comprises a CVD method or a precursor method.

Since the matrix can be filled in the gaps of the aggregate by depositing the raw material gas which is a gas in the CVD method and impregnating the precursor which is a liquid in the precursor method, it is possible to efficiently form the SiC fiber-reinforced SiC composite material. it can.

(6) The strand further contains organic fibers and has an organic fiber removing step of removing the organic fibers between the base material forming step and the SiC coating forming step.

When the strands contain organic fibers in the method for producing a SiC fiber-reinforced SiC composite material of the present invention, it is possible to reduce friction between carbon fibers when molding the aggregate and prevent breakage of the carbon fibers. .. Further, since the organic fibers have been removed by the SiC coating forming step, the SiC coating can be formed to a sufficient thickness in the voids after the organic fibers have been removed.

(7) The organic fiber removing step is performed at the same time as the sizing agent removing step.

Removal of organic fibers and removal of sizing agents can be done in a similar process. Therefore, by appropriately selecting the combination of the organic fiber and the sizing agent, the organic fiber and the sizing agent can be removed at the same time by the same treatment.

In the method for producing a SiC fiber-reinforced SiC composite material of the present invention, a base material is formed using strands composed of carbon fibers and a sizing agent. Since carbon has a hexagonal crystal structure in which the c-axis direction is bonded by a van der Waals force, it has a lubricating action, and it is difficult for a strong force to be applied to the carbon fibers. Therefore, even if the base material is formed in the form of a cloth or the like, the base material is formed at the stage of carbon fibers in which a strong frictional force is unlikely to be generated on the surface, so that the occurrence of fluffing can be reduced. Further, since the strand has a sizing agent, the friction between the fibers is further reduced, making it difficult to cut.

In the method for producing a SiC fiber-reinforced SiC composite material of the present invention, the aggregate is formed by weaving and winding at the stage of carbon fiber. Therefore, at the stage of forming the aggregate, the surface is coated with ceramic as an interface layer. There is no. Therefore, the ceramic coating on the surface does not peel off and damage the ceramic fibers. Therefore, fluffing can be less likely to occur.

(A) is a process flowchart of the method for producing the SiC fiber-reinforced SiC composite material according to the first embodiment of the present invention, and (b) is the process flowchart of the method for producing the SiC fiber-reinforced SiC composite material according to the second embodiment of the present invention. The process flowchart, (c) shows the process flowchart of the manufacturing method of the SiC fiber reinforced SiC composite material of Embodiment 3 which concerns on this invention. In the method for producing a SiC fiber-reinforced SiC composite material according to the first embodiment of the present invention, the schematic diagram is based on an image of a process of forming a SiC fiber-reinforced SiC composite material. FIG. ) Indicates a sizing agent removing step, (c) shows a SiC coating forming step, (d) shows an interface layer forming step, and (e) shows a matrix forming step. In the method for producing a SiC fiber-reinforced SiC composite material according to the second embodiment of the present invention, the schematic diagram is based on an image of a process of forming a SiC fiber-reinforced SiC composite material. FIG. ) Indicates a sizing agent removing step, (c) shows a SiC coating forming step, (d) shows an interface layer forming step, and (e) shows a matrix forming step.

(Detailed description of the invention)
The method for producing a SiC fiber-reinforced SiC composite material of the present invention includes a base material forming step of forming a base material using strands composed of a plurality of carbon fibers and a sizing agent, and sizing for removing the sizing agent from the base material. A chemical removal step, a SiC coating forming step of putting the base material in a CVD furnace and forming a SiC coating on the surface with the carbon fiber as a core, and an interface layer forming step of forming an interface layer on the outside of the SiC coating. A matrix forming step of forming a SiC matrix on the outside of the interface layer is included.

In the method for producing a SiC fiber-reinforced SiC composite material of the present invention, a base material is formed using strands composed of carbon fibers and a sizing agent. Since carbon has a hexagonal crystal structure in which the c-axis direction is bonded by a van der Waals force, it has a lubricating action, and it is difficult for a strong force to be applied to the carbon fibers. Even if the base material is formed in the form of a cloth or the like, the base material is formed at the stage of carbon fibers in which a strong frictional force is unlikely to be generated on the surface, so that the occurrence of fluffing can be reduced. Further, since the strand has a sizing agent, the friction between the fibers is further reduced, making it difficult to cut.

In the method for producing a SiC fiber-reinforced SiC composite material of the present invention, the aggregate is formed by weaving and winding at the stage of carbon fiber. Therefore, at the stage of forming the aggregate, the surface is coated with ceramic as an interface layer. There is no. Therefore, the ceramic coating on the surface is not peeled off and the ceramic fibers are not damaged, and fluffing can be less likely to occur.

The method for producing a SiC fiber-reinforced SiC composite material of the present invention preferably has the following aspects.

The base material forming step comprises at least one of a weaving method of weaving a cloth, a braiding method of knitting a braid body, and a filament winding method of winding a filament winding body.

In the weaving method, the braiding method, and the filament winding method, continuous SiC fibers are combined to form an aggregate with bending. Therefore, when the fibers are cut and fluffing occurs, gaps are formed in the SiC fibers, making it difficult for the SiC matrix to completely fill the gaps, and defects are likely to occur in the SiC matrix. In the method for producing a SiC fiber-reinforced SiC composite material of the present invention, cutting is unlikely to occur even at a bent portion of the SiC fiber, so that the SiC matrix is easily filled between the aggregates to obtain a strong SiC fiber-reinforced SiC composite material. Can be done.

The sizing agent removing step is either a cleaning method or a heating method.

Examples of the sizing agent include epoxy resins, polypropylenes, polyethylenes, vinyl ester resins, silicone resins, hydrazide resins, polyethylene oxides and the like. By removing these sizing agents, SiC can be formed directly on the carbon fibers. The method for removing the sizing agent can be appropriately selected depending on the type of the sizing agent. A water-soluble sizing agent can be washed with water, and a sizing agent soluble in an organic solvent can be washed with an organic solvent. Further, any sizing agent that can be heated to a temperature equal to or higher than the boiling point and sublimation point, and a sizing agent that is thermally decomposed so that no residue remains can be removed by heating, evaporation, sublimation, or thermal decomposition.

Further, in the method for producing a SiC fiber-reinforced SiC composite material of the present invention, after forming a base material, a sizing agent is removed to form a SiC coating to obtain SiC fibers. Since the SiC fiber obtained in the present invention is obtained by the CVD method, it does not contain oxygen like the SiC fiber obtained by spinning the precursor. When oxygen is contained, it reacts with SiC at a high temperature, decomposes into gases such as SiO and CO, and becomes a source of forming defects in SiC fibers. Since the SiC fiber of the present invention has SiC formed in the core of the carbon fiber, it is possible to obtain a SiC fiber-reinforced SiC composite material that does not contain oxygen and has high heat resistance.

In the method for producing a SiC fiber-reinforced SiC composite material of the present invention, an interface layer is formed on the surface of the obtained SiC fiber. The interface layer prevents the SiC fibers from being integrated with the SiC matrix after the SiC fiber-reinforced SiC composite material is formed, and acts so that the SiC fibers are pulled out from the matrix. Therefore, the performance as a composite material without breaking at once. Will be able to demonstrate.

The method for producing a SiC fiber-reinforced SiC composite material of the present invention further includes a matrix forming step of forming a SiC matrix on the outside of the interface layer. In the matrix forming step, a CVD method in which the raw material gas is deposited between the SiC fibers of the aggregate, a precursor method in which the aggregate is impregnated with the resin of the precursor and then thermally decomposed can be used.

The interface layer is made of BN or pyrolytic carbon.

The BN or pyrolytic carbon, which is the interface layer, is a hexagonal crystal and is bonded by van der Waals force in the c-axis direction, so that it has a crystal structure that is easily cleaved. Therefore, when the interface layer is made of these ceramics, the matrix and the SiC fiber as an aggregate prevent integration, and the SiC fiber acts so as to be pulled out from the matrix, so that the performance as a composite material is exhibited. You will be able to do it. The thickness of the interface layer is not particularly limited. The preferred interface layer thickness is, for example, 0.3-10 μm. If it is 0.3 μm or more, it can be diffused and hard to disappear even if it is used for a long period of time. If it is 10 μm or less, the volume of the interface layer in the total volume of the SiC fiber-reinforced SiC composite material can be reduced, so that a high-strength SiC fiber-reinforced SiC composite material can be obtained.

The matrix forming step comprises a CVD method or a precursor method.

Since the matrix can be filled in the gaps of the aggregate by depositing the raw material gas which is a gas in the CVD method and impregnating the precursor which is a liquid in the precursor method, it is possible to efficiently form the SiC fiber-reinforced SiC composite material. it can.

The strand further contains organic fibers and has an organic fiber removing step of removing the organic fibers between the base material forming step and the SiC coating forming step.

When organic fibers are contained in the strands of the method for producing a SiC fiber-reinforced SiC composite material of the present invention, it is possible to reduce friction between carbon fibers when molding the aggregate and prevent breakage of the carbon fibers. .. Further, since the organic fibers have been removed by the SiC coating forming step, the SiC coating can be formed to a sufficient thickness in the voids after the organic fibers have been removed.

The organic fiber removing step is performed at the same time as the sizing agent removing step.

Removal of organic fibers and removal of sizing agents can be done in a similar process. Therefore, by appropriately selecting the combination of the organic fiber and the sizing agent, the organic fiber and the sizing agent can be removed at the same time by the same treatment.

(Form for carrying out the invention)
The method for producing the SiC fiber-reinforced SiC composite material of the present invention will be described below with reference to examples.

<Embodiment 1>
FIG. 1A is a flowchart showing a process of a method for manufacturing a SiC fiber-reinforced SiC composite material according to the first embodiment of the present invention. See FIG. 2 for a schematic diagram of each step in which the SiC fiber-reinforced SiC composite material is formed.

The first embodiment includes a base material forming step S1, a sizing agent removing step S2, a SiC coating forming step S3, an interface layer forming step S4, and a matrix forming step S5.

In the base material forming step S1, the base material 4 in the form of laminating cloths is formed by using the strands 3 of the carbon fibers 2 bundled with the sizing agent 1 (see FIG. 2A). The strand 3 is composed of, for example, 200 to 200 carbon fibers 2 and a sizing agent 1, and does not contain organic fibers. For example, the thickness of the carbon fibers 2 is 3 to 20 μm, and the carbon fibers 2 are grouped into one strand 3 by the sizing agent 1. For example, the sizing agent 1 is an epoxy resin and is a thermosetting resin, so that it is insoluble in a solvent but can be thermally decomposed in an inert gas.

The strand 3 composed of the sizing agent 1 and the carbon fiber 2 is woven into a cloth, and a plurality of strands can be laminated to obtain the base material 4. The base material 4 is not limited to the form of the cloth, and a filament winding body, a braiding body, or the like can be used.

Next, the sizing agent 1 is removed in the sizing agent removing step S2 (see FIG. 2B). The process of the sizing agent removing step S2 can be appropriately selected depending on the type of the sizing agent 1.

If it is a solvent-soluble sizing agent 1, it can be removed by a solvent, and if it is a sizing agent 1 that thermally decomposes in an inert gas, it is thermally decomposed without leaving a residue by heating in an inert gas. Can be done. By removing the sizing agent 1 from the base material 4, the voids in the base material 4 can be increased.

As the solvent, carboxylic acid esters such as ethyl acetate, acetone, ethers, toluene, water and the like can be used. Wash in these solvents to remove the sizing agent 1. Further, when cleaning with a solvent, in order to enhance the penetrating power of the solvent, ultrasonic cleaning, heating or the like may be performed as an auxiliary. When the sizing agent 1 is removed by thermal decomposition, it can be thermally decomposed or volatilized and removed by heating in, for example, air, nitrogen gas, noble gas, or vacuum. In the base material 4 from which the sizing agent 1 has been removed in this way, many voids are formed around the carbon fibers 2.

Next, in the SiC coating forming step S3, the SiC coating 5 is formed around the carbon fibers 2. That is, the SiC coating 5 is formed on the surface of the carbon fiber 2 as a core. Here, the SiC fiber 6 having a carbon fiber core is formed (see FIG. 2C).

In the SiC coating forming step S3, the periphery of the carbon fiber 2 is covered with CVD-SiC (SiC coating 5). Since CVD-SiC does not contain oxygen in the raw material gas, it does not generate gases such as SiO and CO even at high temperatures, and the carbon fiber 2 which is the core material is also stable at high temperatures, so that it has high heat resistance. have.
The thickness of the SiC fiber 6 having the core of the carbon fiber 2 is, for example, 20 to 70 μm.

In the SiC coating forming step S3, it is preferable to adjust the CVD conditions so that the CVD-SiC layer (SiC coating 5) is not concentrated on the surface of the base material 4. The film formation temperature of CVD is, for example, 1000 to 1500 ° C. The pressure in the CVD furnace is, for example, 1 to 100 kPa.

Next, in the interface layer forming step S4, the interface layer 7 is formed on the surface of the obtained SiC fiber 6 (see FIG. 2D).

The interface layer 7 is formed by a CVD method. The interface layer 7 is made of a ceramic different from SiC in order to prevent the SiC fiber 6 and the SiC matrix 8 from being integrated with each other. Examples of the interface layer 7 include BN and pyrolytic carbon. Since these compounds have a hexagonal crystal structure, they have cleavage planes that bond with a weak van der Waals force, prevent the SiC fiber 6 and the SiC matrix 8 from being integrated, and serve as a composite material. It is possible to fully exert the pulling effect of. The pull-out effect means that the composite material is broken while the fibers are pulled out from the matrix, and the breakage does not proceed at once, and the shape can be maintained.

In the interface layer forming step S4, the interface layer is formed by the CVD method. Therefore, in the SiC coating forming step S3, after forming the SiC coating 5 around the carbon fiber 2, the raw material gas and the conditions are appropriately changed, and 1 is continuously formed. It can be manufactured with one device.

Next, in the matrix forming step S5, the SiC matrix 8 is formed on the SiC fiber 6 in which the interface layer 7 is formed (see FIG. 2E).

The method for forming the SiC matrix 8 is not particularly limited, and for example, a CVD method and a precursor method can be used. In the CVD method, the same conditions as in the SiC coating forming step S3 can be performed by appropriately changing the conditions so that the gaps between the SiC fibers 6 can be filled with the SiC matrix 8. Further, in the precursor method, it can be obtained by impregnating a liquid precursor and then firing. The precursor is not particularly limited as long as it can be calcined to obtain SiC, but for example, polycarbosilane and its derivative can be used. Above all, it is preferable to use the CVD method. In the CVD method, since the raw material gas does not contain oxygen, gas such as SiO and CO is not generated even at a high temperature, and the raw material gas has high heat resistance.

The film forming temperature in the CVD method is, for example, 1000 to 1500 ° C. The pressure in the CVD furnace is, for example, 1 to 100 kPa. The firing temperature in the precursor method is 600 to 1200 ° C.

<Embodiment 2>
FIG. 1B is a flowchart showing a process of a method for manufacturing a SiC fiber-reinforced SiC composite material according to a second embodiment of the present invention. See FIG. 3 for a schematic diagram of each step in which the SiC fiber-reinforced SiC composite material is formed in the second embodiment.

In the second embodiment, the strand 3 is composed of the carbon fiber 2, the organic fiber 9, and the sizing agent 1 (see FIG. 3A), and is organic at the same time as the sizing agent removing step S2 in the manufacturing process of the first embodiment. The fact that the fiber removing step S6 is performed is different from the first embodiment (see FIG. 3B).

Any organic fiber 9 can be used without particular limitation, but it is preferable that the organic fiber 9 is a fiber having a finite length so that it can be inserted between the continuous fibers of the carbon fiber 2. For example, a bundle of carbon fibers 2 is defibrated by air blowing, and an organic fiber 9 is inserted between them. After that, the sizing agent 1 is applied to obtain a strand 3 composed of the carbon fiber 2, the organic fiber 9, and the sizing agent 1. As the organic fiber 9, for example, any natural fiber, synthetic fiber, or the like can be used. Among them, synthetic fibers use purified raw materials, so that impurities are less mixed, and since thermoplastic resins are mainly used, they can be easily removed with a solvent and residues can be made less likely to remain.

Further, in the sizing agent removing step S2, the organic fiber removing step S6 is also performed at the same time.
The method of the sizing agent removing step S2 performed at the same time as the organic fiber removing step S6 is not particularly limited by any method, but in this case, it is necessary that the organic fiber 9 and the sizing agent 1 can be removed by the same method. ..
As a removal method, a heating method can be used as long as thermal decomposition is possible without leaving a residue, and a cleaning method in which cleaning is performed in a solvent can be used if there is a common solvent.

<Embodiment 3>
FIG. 1C is a flowchart showing a process of a method for manufacturing a SiC fiber-reinforced SiC composite material according to a third embodiment of the present invention.
The only difference between the third embodiment is that the sizing agent removing step S2 and the organic fiber removing step S6 are not performed at the same time as in the second embodiment, and the organic fiber removing step S6 is performed after the sizing agent removing step S2. Is.
Since the sizing agent removing step S2 and the organic fiber removing step S6 are not performed at the same time, a removal method suitable for each can be selected.

When natural fibers are used as the organic fibers 9, there are few good solvents that are easily available, so it is preferable to use a heating method in which the organic fibers are fired and thermally decomposed. When synthetic fibers are used as the organic fibers 9, many fibers are soluble in a solvent, so a cleaning method in which a solvent is appropriately selected and removed with the solvent can be used, and a heating method for thermal decomposition can also be used. Can be done.

The order is not particularly limited to the method of this embodiment, and the order of the organic fiber removing step S6 and the sizing agent removing step S2 is not particularly limited, and either of them may be performed first or may be performed at the same time.

The present invention is not limited to the above-described embodiment, and can be appropriately modified, improved, and the like. In addition, the material, shape, size, numerical value, form, number, arrangement location, etc. of each component in the above-described embodiment are arbitrary and are not limited as long as the present invention can be achieved.

The method for producing a SiC fiber-reinforced SiC composite material of the present invention is a field for producing a SiC fiber-reinforced SiC composite material used for a jet engine member, a gas turbine member, and the like, in addition to a channel box for a nuclear reactor member and a fuel cladding tube. It is compatible with.

1 Sizing agent 2 Carbon fiber 3 Strand 4 Base material 5 SiC coating 6 SiC fiber 7 Interface layer 8 SiC matrix 9 Organic fiber S1 Base material forming process S2 Sizing agent removal process S3 SiC coating forming process S4 Interface layer forming process S5 Matrix forming process S6 Organic fiber removal step

Claims (7)

A base material forming step of forming a base material using strands composed of a plurality of carbon fibers and a sizing agent, and
A sizing agent removing step of removing the sizing agent from the base material,
A SiC coating forming step of placing the base material from which the sizing agent has been removed into a CVD furnace and forming a SiC coating on the surface of the carbon fibers as a core.
An interface layer forming step of forming an interface layer on the outside of the SiC coating, and
A matrix forming step of forming a SiC matrix on the outside of the interface layer,
A method for producing a SiC fiber-reinforced SiC composite material including. The SiC fiber-reinforced SiC according to claim 1, wherein the base material forming step comprises at least one of a weaving method of weaving a cloth, a braiding method of knitting a braid body, and a filament winding method of winding a filament winding body. Method for manufacturing composite materials. The method for producing a SiC fiber-reinforced SiC composite material according to claim 1 or 2, wherein the sizing agent removing step is either a cleaning method or a heating method. The method for producing a SiC fiber-reinforced SiC composite material according to any one of claims 1 to 3, wherein the interface layer is made of BN or pyrolytic carbon. The method for producing a SiC fiber-reinforced SiC composite material according to any one of claims 1 to 4, wherein the matrix forming step comprises a CVD method or a precursor method. The strand according to any one of claims 1 to 5, further containing organic fibers and having an organic fiber removing step of removing the organic fibers between the base material forming step and the SiC coating forming step. The method for producing a SiC fiber-reinforced SiC composite material according to the above method. The method for producing a SiC fiber-reinforced SiC composite material according to claim 6, wherein the organic fiber removing step is performed at the same time as the sizing agent removing step.

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