JP2000256064A - Composite material impregnated with highly oxidation resistant si and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel composite material impregnated with highly oxidation resistant Si improved on oxidation resistance at an elevated temperature. SOLUTION: This composite material impregnated with the highly oxidation resistant Si consists of a yarn array body, an Si-SiC-base material phase 5 which is formed by melting metal silicon, silicon carbide and boron carbide to impregnate the inside of the open cells of a fired body obtained by molding and firing the yarn array body, etc., by using a binder containing none of the metal silicon, silicon carbide and boron carbide, with the metal silicon, silicon carbide and boron carbide, a skeletal part mainly consisting of carbon fibers and an Si-SiC-base material formed around the skeletal part and a matrix 8 formed of the boron carbide. In this case, the matrix and the skeletal part are integrally formed and have a porosity of <=10%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention can be used as various working members that require oxidation resistance at high temperatures, that is, jigs for molten metal, members for grinding, various molds, members for manufacturing equipment, and the like. Novel high oxidation resistant Si-impregnated composite material and a method for producing the same.

[0002]

[Prior art] With technological innovation in various industrial fields,
There is an increasing need for various members that can be used under higher temperature conditions. In particular, as a member for heat treatment of metal products, glass products, and ceramic products that require rapid repetitive heating and cooling, or as a member for manufacturing equipment for these products, it can be formed into a lightweight and desired shape. At present, the appearance of a material excellent in thermal shock resistance has been demanded. Materials satisfying such requirements include various ceramic materials, carbon, and a carbon fiber composite carbon material referred to as a so-called C / C composite. However, ceramic materials have a disadvantage that they are inferior in thermal shock resistance and are relatively easily cracked. On the other hand, carbon and C
Although the / C composite is excellent in thermal shock resistance, its use atmosphere is limited because the material is carbon. In other words, there is a problem that it cannot be used at all because it reacts with oxygen and burns in an atmosphere where oxygen or moisture is present. Therefore, at present, there is no material having both excellent thermal shock resistance and oxidation resistance.

[0003]

SUMMARY OF THE INVENTION The present invention can be used as various working members which can be used under higher temperature conditions. In particular, metal products, glass products, and the like which are required to be repeatedly heated and cooled rapidly. As a member for heat treatment such as ceramic products, or as a member for manufacturing equipment such as these metal products, glass products, and ceramic products, it is lightweight, can be easily formed into a desired shape, and has high resistance to oxidation at high temperatures. high,
An object of the present invention is to provide a novel high oxidation resistant Si-impregnated composite material having excellent thermal shock resistance, and a method for producing the same. Another object of the present invention is to provide a novel highly oxidation-resistant Si-impregnated composite material having high oxidation resistance, which can be used as various members used at an ultra-high temperature, and a method for producing the same.

[0004]

Means for Solving the Problems As a result of various studies to achieve the above object, the present inventors have found that silicon carbide, metallic silicon, carbon substantially consisting of carbon fibers, and even if desired, A high-oxidation-resistant Si-impregnated composite material having a structure including a skeleton portion and a matrix formed around the skeleton portion, the composite material comprising:
At least 50% of the silicon carbide is β-type, and the skeleton portion is made of Si-SiC composed of a carbon fiber bundle, silicon carbide formed in or around the carbon fiber bundle, and metallic silicon.
The base material is formed from boron carbide which may be optionally contained, and the matrix is made of a Si-SiC-based material composed of silicon carbide and metallic silicon, and boron carbide which may be optionally contained. The matrix and the skeleton are formed integrally with each other, and the composite material achieves the above object by a highly oxidation-resistant Si-impregnated composite material having a porosity of 10% or less. And completed the present invention.

[0005] Furthermore, a yarn and a yarn comprising a carbon fiber bundle in which at least either metallic silicon or silicon carbide and optionally boron carbide are added to the bundle of carbon fibers, and / or A yarn array and a yarn array, a molded article molded using a binder to which at least one material selected from metallic silicon and silicon carbide and optionally boron carbide added may be contained, or A step of firing a molded body molded using a binder not containing any of the metal silicon, silicon carbide, and boron carbide to form a fired body, and in the obtained fired body, if desired, metallic silicon; At least one material selected from silicon carbide and boron carbide is added, and then the weight of the fired body and the total weight of metallic silicon and silicon carbide contained in the fired body While flowing an inert gas of 0.1 NL or more per kg of the total weight of
After holding at 00 to 1400 ° C. and a furnace pressure of 0.1 to 10 hPa for 1 hour or more, the temperature is raised to 1450 to 2500 ° C. and metal silicon and / or silicon carbide and, if desired, into the open pores of the fired body. The boron carbide which may be contained is melted and impregnated to form a Si-SiC-based material phase, and the boron carbide which may be contained if necessary
A step of forming a matrix composed of the Si-SiC-based material phase and, if desired, the boron carbide phase by being integrally formed with the SiC-based material phase, and further covering the outermost surface of the fired body obtained as desired with boron carbide The present invention has been found to produce the above-mentioned highly oxidation-resistant Si-impregnated composite material, thereby completing the present invention. Further, according to the present invention, at least a part of the composite material is silica-
A highly oxidation resistant Si-impregnated composite having a boron oxide phase formed is provided.

The high oxidation resistant Si-impregnated composite material according to the present invention basically comprises from 25% to 65% by weight of carbon,
It is composed of 1% by weight to 10% by weight of metallic silicon, 10% by weight to 50% by weight of silicon carbide, and 0% by weight to 10% by weight of boron carbide, and comprises at least a Si-SiC-based material and a boron carbide phase. A matrix is integrally formed between the three-dimensionally assembled and non-separated yarn assemblies of carbon fibers. Of course, boron carbide is an optional component, but is preferably contained at least 0.1% by weight in order to further enhance oxidation resistance. By the way, as described later, Si-Si
In order to form a C-based material, the thickness is preferably at least 0.01 mm. Further, it is preferably at least 0.05 mm or more, and more preferably at least 0.1 mm or more.

[0007] The carbon substantially consists of carbon fibers. Substantially made of carbon fiber may contain trace amounts of graphite-derived free carbon formed on the surface of the carbon fiber itself or derived from an auxiliary material such as a binder. Means, in principle, made of carbon fiber. Furthermore, in the novel highly oxidation resistant Si-impregnated composite material according to the present invention, it is preferable that the matrix has a gradient composition in which the content ratio of silicon increases as the matrix moves away from the yarn. In addition, the above high oxidation resistant Si impregnated composite material has a porosity of 1
It is controlled to 0% or less, preferably 0.5% to 3%.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION A highly oxidized Si-impregnated composite material according to the present invention is a Si—SiC formed of silicon carbide and metallic silicon formed in a carbon fiber bundle, in a carbon fiber bundle, or around a carbon fiber bundle. System material, a skeleton formed of boron carbide which may be optionally contained, a Si-SiC-based material composed of silicon carbide and metallic silicon, and boron carbide which may be optionally contained. The matrix and the skeleton portion are formed integrally with each other, and are formed of a composite material composed of ceramic and carbon having a porosity of 10% or less.

As described above, the highly oxidation-resistant Si-impregnated composite material according to the present invention comprises silicon carbide, metallic silicon, carbon substantially consisting of carbon fibers, and optionally boron carbide. A highly oxidized Si-impregnated composite material having a structure comprising a skeleton portion, a matrix formed around the skeleton portion, and formed around the carbon fiber bundle and the carbon fiber bundle. Si-SiC-based material composed of silicon carbide and metal silicon, a skeleton formed of boron carbide which may be contained as desired, and Si-Si composed of silicon carbide and metal silicon
A composite material having a matrix formed of a C-based material and optionally contained boron carbide, or a silica-boron oxide phase is partially formed.

[0010] The skeleton portion is prepared by incorporating a powdery binder and, if necessary, a phenol resin powder or the like into a bundle of carbon fibers to prepare a carbon fiber bundle, and surrounding the carbon fiber bundle with a thermoplastic resin or the like. Form a flexible film made of plastic, obtain a preformed yarn as a flexible intermediate material,
This preformed yarn is formed into a sheet or a woven fabric by the method described in Japanese Patent Application Laid-Open No. 2-80639, and after laminating a required amount, a molded article obtained by molding by hot pressing is obtained. Are preferred. Of course, it may be derived from a fired body obtained by firing this molded body. Here, the binder is a powdery material that acts as a matrix of a formed body or fired body made of a carbon fiber bundle before impregnation with metallic silicon and / or silicon carbide,
It refers to a material containing pitch and coke which become free carbon with respect to the bundle of carbon fibers after firing.

In the present specification, a C / C composite is generally formed by bundling hundreds to tens of thousands of carbon fibers having a diameter of about 10 μm to form a fiber bundle (yarn). A preformed yarn was prepared by coating with a resin, and the preformed yarn was formed into a sheet or a woven fabric by the method described in JP-A-2-80639, and this sheet or woven fabric was formed. By arranging the objects in two-dimensional or three-dimensional directions to form a one-way sheet (UD sheet) or various cloths, or by laminating the above sheets or cloths, a preformed body (fiber preform) having a predetermined shape is formed. Formed and baked a film of a thermoplastic resin or the like made of an organic substance formed on the outer periphery of the fiber bundle of the preformed body,
It is obtained by carbonizing and removing the above film. In this specification, for reference, Japanese Patent Application Laid-Open
Reference is made to the description in JP-A-80639. C according to the present invention
In the / C composite, the carbon component other than the carbon fibers in the yarn is preferably a carbon powder, particularly preferably a graphitized carbon powder.

[0012] In order to form a phase consisting of a Si-SiC-based material and optionally contained boron carbide inside the yarn, at least metallic silicon or silicon carbide is optionally contained during preparation of the preformed yarn. May be mixed in a predetermined amount. In order to form a phase comprising a Si-SiC-based material and optionally contained boron carbide on the surface of the yarn, when preparing a sheet or cloth from a preformed yarn, at least metallic silicon or silicon carbide is required. And a predetermined amount of boron carbide which may be contained if desired. The mixing method is a method of directly mixing metallic silicon and / or silicon carbide and, if desired, boron carbide between carbon fibers constituting the yarn or between the yarns, or a yarn such as a binder or a phenol resin. ,
There is an indirect mixing method in which a yarn array is mixed or used with various auxiliaries used when preparing a sheet or a cloth by laminating the yarn array. For uniform mixing, an indirect mixing method is preferred.

The amount of silicon metal and / or silicon carbide used depends on the design performance, but is usually about 11% to 60% based on the total weight of the highly oxidation-resistant Si-impregnated composite material according to the present invention. It is enough in the range of. The amount of boron carbide that may be contained as desired is in the range of 0 to 10% based on the total weight of the high oxidation resistant Si-impregnated composite material. Of course, the phase composed of the Si—SiC-based material and optionally contained boron carbide is at least
As long as it is formed as a matrix, it is not necessary to impregnate these materials into either the inside of the yarn or the surface of the yarn according to the required performance for each application.

In the highly oxidation-resistant Si-impregnated composite material according to the present invention, as a material constituting the skeleton, a carbon fiber bundle formed of a plurality of carbon fibers, preferably
A carbon fiber bundle having a C / C composite as described above is used. On the surface and / or inside of the carbon fiber constituting each yarn, a Si—SiC-based material and a boron carbide phase which may be formed as desired are formed. However, at least a part of the carbon fibers constituting each carbon fiber bundle needs to have a structure as a carbon fiber that is maintained without being destroyed by a reaction with metallic silicon and / or silicon carbide. Thereby, the mechanical strength inherent to the carbon fiber is substantially maintained. Therefore, as the carbon fiber, at least a part of the carbon fiber,
A C / C composite having a structure that easily remains without being converted to silicon carbide is preferable. In addition, Si- in the carbon fiber bundle and between the adjacent yarns in the yarn assembly.
Since it has a structure in which a matrix made of a SiC-based material and optionally boron carbide is formed, the oxidation resistance is enhanced.

In the present invention, the Si—SiC-based material is a general term for a material containing silicon and silicon carbide as main components. This Si-SiC-based material is formed by a reaction between carbon fiber and metallic silicon or silicon carbide, which is formed when the high oxidation resistant composite material according to the present invention is manufactured. For example, a yarn array formed from a carbon fiber bundle and a yarn array are combined with a binder to which metal silicon and / or silicon carbide has been added to obtain a molded body, which is carbonized at 700 to 1200 ° C. 1500-3
Sintering at 000 ° C. to react at least partially silicon carbide formed by reacting carbon fibers and free carbon mainly derived from a binder present on the surface of the carbon fibers with metallic silicon and / or silicon carbide. It is a material in which a phase composed of only the metal and a phase in which metallic silicon remains unreacted continuously change.

That is, the Si—SiC-based material includes several different phases ranging from a silicon phase remaining in an unreacted state to almost pure silicon carbide, typically silicon. Phase and a silicon carbide phase.
Coexisting phases may be included. Therefore, the Si-SiC-based material is
As described above, in the Si-SiC series, it is a general term for materials contained in the range of 0 mol% to 50 mol% as the concentration of carbon. In the high oxidation resistant composite member according to the present invention, the Si-SiC-based material may be formed not only in the matrix portion but also in the carbon fiber bundle and / or on the surface of the carbon fiber bundle.

The highly oxidation-resistant Si-impregnated composite material preferably has a matrix having a gradient composition in which the silicon content increases as the distance from the yarn surface increases. Further, in this highly oxidation-resistant Si-impregnated composite material, preferably, the yarn aggregate made of carbon fibers is composed of a plurality of yarn arrays, and each yarn array bundles a specific number of carbon fibers. The yarns thus formed are formed by arranging the two-dimensionally substantially parallel two-dimensionally, and a yarn aggregate is formed by laminating the yarn arrangements. As a result, the highly oxidation-resistant Si-impregnated composite material has a multilayer structure in which a plurality of yarn arrays are stacked in a specific direction.

In this case, from the viewpoint of the strength of the matrix, it is particularly preferable that the longitudinal directions of the yarns in the adjacent yarn arrays cross each other. Thereby, the dispersion of the stress is further promoted. The longitudinal directions of the yarns in adjacent yarn arrangements are particularly preferably orthogonal. Preferably, the matrix is continuous with each other in the highly oxidation-resistant Si-impregnated composite material to form a three-dimensional network structure. In this case it is particularly preferred that the matrix is arranged two-dimensionally substantially parallel in each yarn arrangement,
The matrices produced in each adjacent yarn arrangement are continuous with one another, whereby the matrices form a three-dimensional lattice. Further, the gap between adjacent yarns may be filled with 100% matrix, but also includes a case where a part of the gap between yarns is filled with matrix.

The highly oxidation-resistant Si-impregnated composite material according to the present invention comprises a Si—SiC-based material and optionally a boron carbide as a matrix, as a matrix, as shown in FIG. Of course, a phase composed of a Si—SiC-based material and optionally contained boron carbide may be formed inside and / or on the same surface of the carbon fiber bundle. . Boron carbide, which may be optionally contained inside and / or on the surface of the matrix and / or carbon fiber bundle, is integrated with the Si-SiC-based material at these points,
Alternatively, they may be independently scattered like islands in the sea made of Si-SiC-based material. As described above, the basic skeleton of the composite fiber is reinforced by the Si—SiC-based material and the boron carbide that may be optionally contained, so that the oxidation resistance is enhanced. When boron carbide is contained, the oxidation resistance at high temperatures is drastically increased, which is preferable. More preferably, the phase of boron carbide is preferably formed on the outermost surface of the composite material impregnated with high oxidation resistance Si according to the present invention, from the viewpoint of improving oxidation resistance.

The highly oxidation-resistant Si-impregnated composite material according to the present invention comprises a carbon fiber bundle having an inner surface and / or a surface
A specific number of yarns on which a SiC-based material phase may be formed are arranged inside and / or on the surface.
C having a three-dimensional structure consisting of a yarn aggregate formed by laminating a yarn array in which an iC-based material phase is formed
The composite material is composed of a skeleton portion made of a / C composite and a Si—SiC-based material formed into a three-dimensional lattice as a matrix between the yarns when the skeleton portion is formed. The high oxidation resistant Si-impregnated composite material according to the present invention has a dynamic friction coefficient at room temperature in the range of 0.1 to 0.5, and has oxidation resistance, creep resistance, and spalling resistance. -By arranging a matrix layer made of a SiC-based material on the surface, it is possible to overcome the low oxidation resistance of the C / C composite, and to use it for sliding materials and brakes which are inevitably exposed to high temperatures in the presence of oxygen. It can be used as a member or the like.

The porosity is 10% or less, preferably
Since it is controlled to be 0.5% to 3%, the fluctuation amount of the dynamic friction coefficient due to a change in the surrounding environment is extremely small, and stable braking performance is exhibited. The amount of wear under high temperature conditions is 5
1.0% / hour or less at 00 ° C, more preferably 0.6%
/ Hour or less. In addition, it has abrasion resistance that incorporates the excellent abrasion resistance inherent to silicon carbide. Further, the highly oxidation-resistant Si-impregnated composite material according to the present invention exhibits extremely excellent oxidation resistance even in a high-temperature atmosphere maintained at 600 ° C. That is, the weight loss in the same high temperature atmosphere containing 1% oxygen is 25% or less, and the weight loss in the same high temperature atmosphere containing 1,000 ppm oxygen is 3% or less.
The amount of weight loss in the high-temperature atmosphere containing oxygen of ppm is substantially zero, and shows extremely high oxidation resistance. This is presumably because, as described above, the Si-SiC-based material phase is also formed inside and / or on the surface of the carbon fiber in addition to the matrix portion.

In the case of the highly oxidation-resistant Si-impregnated composite material according to the present invention, not only is the Si—SiC-based material phase forming a matrix, but also the interior and / or surface of the yarn and / or the yarn array. Since the Si-SiC-based material is melted into glass to protect the skeleton from oxygen faster than the diffusion rate of oxygen into the skeleton, it was used as the skeleton. The situation where the carbon fiber is oxidized by the diffused oxygen can be avoided, and the skeleton can be protected from oxidation. Therefore, the highly oxidation-resistant Si-impregnated composite material according to the present invention exhibits self-healing properties and can be used for a longer period of time. This phenomenon becomes more remarkable when boron carbide is contained. Although the reason is not clear, oxygen and boron carbide, silicon carbide and / or metal silicon are simultaneously oxidized, and a glass phase composed of boron oxide and silica is formed on the carbon fiber surface, so-called covering the surface. This is probably due to the glazing phenomenon.

Unlike the case where only silicon carbide and / or metal silicon is used, when boron carbide is also contained,
It is presumed that the simultaneous oxidation of boron carbide promotes the glazing phenomenon. Therefore, it is necessary to repeatedly perform rapid temperature rise and cooling of metal products, glass products, various mold members used when processing ceramic products, etc., or these metal products, glass products, ceramics It can be used as a member for a manufacturing device such as a product.

As described above, as a result of the glazing, the composite member according to the present invention that is no longer glazed is made of silicon carbide, metal silicon, carbon substantially composed of carbon fiber, silica-oxidized A highly oxidation-resistant Si-impregnated composite material having a structure comprising a skeleton, a matrix formed around the skeleton, and boron, wherein at least 50% of the silicon carbide is β-type, and the skeleton is , A carbon fiber bundle, a Si-SiC-based material composed of silicon carbide and metal silicon formed in or around the carbon fiber bundle, and silica-boron oxide integrally formed with the material And Si-S composed of silicon carbide and metallic silicon
The matrix and the skeleton are formed integrally from an iC-based material and a silica-boron oxide phase integrally formed with the material, and the composite material is 10% or less. High oxidization resistance
It becomes an impregnated composite material.

Of course, forcibly, the matrix is made of a Si—SiC-based material composed of silicon carbide and metallic silicon;
It is also possible to manufacture a highly oxidation-resistant Si-impregnated composite material formed of boron carbide which may be optionally contained by accelerating oxidation. Here, the term “integrally” means not only the case where both are integrally united, but also the case where the existence of both is independently recognized.
It is included unless both are easily separated by a weak mechanical impact. Therefore, this includes a state where islands of boron carbide are scattered in the sea of the Si—SiC-based material.

[0026] Further, since the skeleton portion is configured by using a yarn aggregate formed of a carbon fiber bundle as a basic structure, the material is light in weight and meets the demand for energy saving. In particular, even after the formation of the matrix, the carbon fibers are not shortened, so that the mechanical strength is maintained, and in the yarn assembly, the longitudinal directions of the fibers of each yarn array cross each other, preferably are orthogonal. Therefore, there is no anisotropy of the shape. The matrix composed of free carbon formed on the skeleton is also rich in uniformity. Therefore, the high oxidation-resistant S according to the present invention produced by impregnating this with metallic silicon
In the i-impregnated composite material, metallic silicon is uniformly dispersed and reacts with carbon, so that the composition of the constituent material in a specific volume is uniform. Since the composition is uniform, there is no uneven distribution of internal stress. Therefore, deformation is less likely to occur even when fired, and an effect of producing a large-sized and complicated-shaped molded product, especially a thin-walled large-sized molded product having a complicated shape can be produced.

Furthermore, since the skeleton is a carbon fiber bundle, it has high toughness, and has excellent impact resistance and high hardness.
Therefore, it has become possible to overcome the high-temperature abrasion resistance, which is a drawback of carbon fibers, while maintaining the characteristics of carbon fibers used conventionally. In addition, since continuous open pores are formed between the yarns made of carbon fiber bundles, the pores are impregnated with metallic silicon and / or silicon carbide and, if desired, boron carbide to be formed. The phase formed from the Si—SiC-based material as the matrix and optionally contained boron carbide has a continuous structure and a three-dimensional network structure. Therefore, no matter which part is cut out, it has high abrasion resistance as compared with the carbon fiber used as the skeleton part, and the high heat radiation property, flexibility, and the like originally possessed by the carbon fiber are maintained.

Regarding the structural characteristics of the high oxidation resistant Si-impregnated composite material according to the present invention, Si-
An example in which only a SiC-based material is formed will be described further with reference to the drawings. FIG. 1 is a schematic perspective view for explaining a skeleton portion of a highly oxidized Si-impregnated composite material according to the present invention. FIG. FIG. 3 is a cross-sectional view illustrating a cross-sectional structure of a composite member according to one embodiment, with a partial structure omitted, for describing a formation state of a SiC-based material.

The skeleton of the high oxidation resistant Si-impregnated composite material 7 is constituted by a yarn aggregate 6 as shown in FIG. The yarn aggregate 6 includes the yarn arrays 1A, 1
B, 1C, 1D, 1E, and 1F are vertically stacked. In each yarn array, the yarns 3 are two-dimensionally arranged, and the longitudinal directions of the yarns are substantially parallel. The longitudinal direction of each yarn in each vertically arranged yarn array is orthogonal. That is, the longitudinal direction of each yarn 2A of each yarn array 1A, 1C, 1E is parallel to each other, and each yarn array 1B, 1D, 1F.
Are orthogonal to the longitudinal direction of each yarn 2B. Each yarn is composed of a fiber bundle 3 made of carbon fiber and a carbon component other than carbon fiber. The yarn assembly 6 having a three-dimensional lattice shape is formed by stacking the yarn arrays. Each yarn is crushed during a pressing step, as described below, and is substantially oval.

In each of the yarn arrangements 1A, 1C, and 1E, a gap between adjacent yarns is filled with a matrix 8, and each matrix 8 extends along the surface of the yarn 2A in parallel with the yarn 2A. Each yarn array 1
In B, 1D and 1F, another matrix 8 is formed in the gap between each adjacent yarn, and this matrix 8 extends along the surface of the yarn 2B and in parallel with it. As shown in FIG. 2, the matrix 8 made of a Si—SiC-based material is formed so as to cover the surface of each yarn. In the embodiment shown in FIG. 2, a Si—SiC-based material phase is formed inside the yarn that is a carbon fiber bundle inside the composite member.

Each matrix 8 is elongated, preferably linear, along the surface of the yarn, respectively.
Each matrix 8 is orthogonal to each other. And the matrix 8 in the yarn arrays 1A, 1C, 1E
And the matrix 8 in the yarn arrays 1B, 1D, and 1F orthogonal to the yarn arrays 1B, 1D, and 1F are continuous at the gaps between the yarns 2A and 2B. As a result, matrix 8
Form a three-dimensional lattice as a whole. Si-S
The iC-based material phase preferably has a gradient composition in which the silicon concentration increases as the distance from the surface of the adjacent carbon fiber increases. As a material for a member for a brake, a member for a grinding, or the like, it is preferable that the surface of the highly oxidation-resistant Si-impregnated composite material is formed from a Si-SiC-based material phase.

Here, the thickness of the matrix layer formed by impregnating the sintered body with the Si—SiC-based material is preferably at least 0.01 mm. Further, it is preferably at least 0.05 mm, more preferably at least 0.1 mm. When the thickness of the matrix layer is less than 0.01 mm,
This is because the durability required as a sliding material cannot be sufficiently imparted under high oxidation conditions.

In the high oxidation resistant Si-impregnated composite material according to the present invention, the concentration of silicon present in the Si—SiC-based material phase in a state of being bonded to carbon increases from the surface of the adjacent carbon fiber toward the inside. Preferably, it is smaller. By providing a gradient in the silicon concentration inside and / or on the surface of the matrix and the yarn and / or the yarn array, corrosion resistance and strength in a strong oxidative corrosion environment, and a healing function against defects in the surface layer and the inner layer are improved. It can be significantly improved, and furthermore, the thermal stress deterioration of the material due to the difference in thermal expansion coefficient can be prevented. This is because the silicon concentration in the surface layer portion is relatively higher than the silicon concentration in the inner layer portion, so that the generated microcracks are healed during heating and maintain oxidation resistance. In particular, the present invention includes a mode in which a Si-SiC-based material phase is formed inside and / or on the surface of the yarn and / or the yarn array. By including this mode, an unexpectedly unexpected abnormal Even if a part of the carbon fiber is exposed on the surface due to the application of the stress, the Si formed inside and / or on the surface of the yarn and / or the yarn array is formed.
-Exerts an effect that the SiC-based material phase exhibits self-healing properties.

The boron carbide that may be contained in the highly oxidation-resistant Si-impregnated composite material of the present invention has lubricity.
Even in the skeleton portion where the Si-SiC-based material is formed, the lubricity of the fiber can be maintained, and a decrease in toughness can be prevented. In addition, for example, the content of boron carbide is 0.1% with respect to 100% by weight of the skeleton portion made of carbon fiber.
Preferably it is 1 to 10% by weight. If it is less than 0.1% by weight, the effect of imparting lubricity by boron carbide cannot be sufficiently obtained, and if it exceeds 10% by weight, the brittleness of boron carbide also appears in the high oxidation resistant Si-impregnated composite material. is there.

As described above, the high oxidation resistant Si-impregnated composite material of the present invention provides the impact resistance, high hardness and light weight of a C / C composite, and the oxidation resistance of a Si—SiC-based material.
It has spalling resistance, self-lubrication, abrasion resistance, etc., and also has self-healing properties, so it can withstand long-term use under high-temperature oxidation conditions.
It can be suitably used as a brake member or the like.

The highly oxidation-resistant Si-impregnated composite material according to the present invention can be preferably manufactured by a method described in detail below. A yarn and a yarn comprising a carbon fiber bundle of carbon fibers in which at least one kind of material selected from metallic silicon and silicon carbide and optionally boron carbide may be added, and And / or a binder obtained by adding at least one material selected from metal silicon and silicon carbide to the yarn array and the yarn array and a boron carbide that may be optionally contained, or And a step of firing a molded body molded using a binder not containing any of boron carbide, and a step of forming a fired body, the resulting fired body, if desired, selected from silicon metal, silicon carbide and boron carbide Then, at least one kind of material was added, and then a total weight of 1 kg of the weight of the fired body and the total weight of metal silicon and silicon carbide contained in the fired body was applied. While flowing an inert gas of 0.1 NL or more, the furnace temperature is maintained at 1100 to 1400 ° C. and the furnace pressure is 0.1 to 10 hPa for 1 hour or more to melt metal silicon and silicon carbide into the open pores of the fired body. , To form a Si-SiC-based material phase,
A step of forming a matrix composed of the Si-SiC-based material phase and optionally contained boron carbide by, for example, dispersing boron carbide in the C-based material phase if desired; By coating with boron carbide, a highly oxidation-resistant Si-impregnated composite material is produced.

First, the highly oxidation-resistant Si-impregnated composite material according to the present invention contains at least one material selected from metallic silicon and silicon carbide in carbon fiber, and carbon dioxide which may be optionally contained. A yarn and a yarn composed of a carbon fiber bundle of carbon fibers to which boron is added, and / or a yarn array and a yarn array configured by arranging the yarns, at least one kind selected from metallic silicon and silicon carbide By sintering the molded article using a material and a binder to which boron carbide optionally contained is added, carbon fibers and / or the surface of the yarn can be formed.
It can also be manufactured by a step of forming a fired body containing at least one kind of material selected from metallic silicon and silicon carbide and optionally containing boron carbide.

Second, the highly oxidation-resistant Si-impregnated composite material according to the present invention includes at least one material selected from metallic silicon and silicon carbide in a carbon fiber, and a carbonized material that may be optionally contained. Molding in which a yarn and a yarn, and / or a yarn array and a yarn array, each formed of a carbon fiber bundle of boron-added carbon fibers are formed using a binder not containing any of silicon metal, silicon carbide, and boron carbide. Firing the body to form a fired body, adding metallic silicon and / or silicon carbide and, if desired, boron carbide to the obtained fired body, and then adding the weight of the fired body and the metal contained in the fired body Total weight of silicon and silicon carbide 1k
While flowing an inert gas of 0.1 NL or more per g, furnace temperature 1100 to 1400 ° C., furnace pressure 0.1 to 10 hPa
After holding for 1 hour or more at a temperature of 1450-2500 ° C
To form an Si-SiC-based material phase by melting and impregnating metallic silicon and / or silicon carbide and optionally boron carbide into the open pores of the fired body. -By dispersing boron carbide optionally contained in the SiC-based material phase,
It can also be produced from a step of forming a matrix composed of an i-SiC-based material phase and optionally contained boron carbide. When boron carbide is not contained, the temperature for melting and impregnating is 1700 to 1800 ° C.
Is preferred.

Third, the highly oxidized Si-impregnated composite material according to the present invention comprises a step of forming a fired body by the first method, and then, the obtained fired body is subjected to the same method as in the second method. ,
Metallic silicon and / or silicon carbide and, if desired, boron carbide are added. Then, the weight of the fired body and the total weight of all metal silicon and silicon carbide contained in the fired body are not less than 0.1 NL per kg. While flowing the active gas, 1 at a furnace temperature of 1100 to 1400 ° C. and a furnace pressure of 0.1 to 10 hPa.
After holding for at least one hour, the temperature is raised to 1450 to 2500 ° C. to melt and impregnate metal silicon and / or silicon carbide and optionally boron carbide into the open pores of the fired body, By forming a Si—SiC-based material phase and dispersing boron carbide that may be optionally contained in the Si—SiC-based material phase,
It can also be produced from a step of forming a matrix composed of a SiC-based material phase and optionally contained boron carbide. If it does not contain boron carbide,
The temperature for melting and impregnating is preferably 1700 to 1800 ° C.

Fourth, the high oxidation resistant Si-impregnated composite material according to the present invention can be produced by spraying boron carbide on the outermost surface of the composite material obtained by any of the above methods and coating the outermost surface. It is possible. Further, the carbon fiber bundle is coated with a plastic such as a thermoplastic resin by the method described in JP-A-2-80639 to obtain a preformed yarn, which is then formed into a sheet or a woven fabric, and a laminate is produced therefrom. , A molded body to be molded from now, or
A fired body of the molded body, that is, a body using a C / C composite may be used. In the case of C / C composite,
Metallic silicon and / or silicon carbide and, if desired, boron carbide may be added to the carbon fibers or to the binder. Further, it may be added to the fired body. There is no particular limitation on the method of addition, regardless of which method is employed. The addition may be performed by a method considered appropriate according to the timing of the addition.

Next, in the above second manufacturing method,
The case where the C / C composite is used will be described further as an example. A carbon fiber bundle is produced by incorporating a powdery binder pitch and coke finally serving as a matrix into the carbon fiber bundle and further including a phenol resin powder or the like as necessary.
A flexible film made of a plastic such as a thermoplastic resin is formed around the carbon fiber bundle to obtain a preformed yarn. After making this preformed yarn into a yarn and laminating a required amount, the hot press is performed at 300 to 2000 ° C.
A molded article is obtained by molding under the conditions of Josho to 500 kg / cm ² . Alternatively, the molded body is carbonized at 700 to 1200 ° C. as necessary,
It is graphitized at 0 ° C. to obtain a sintered body.

The carbon fiber is obtained by preparing pitch for spinning, melt-spinning, infusibilizing and carbonizing pitch-based carbon fiber and acrylonitrile (co) polymer fiber by using petroleum pitch or coal tar pitch as a raw material. Any of the obtained PAN-based carbon fibers may be used. The carbon precursor necessary for the formation of the matrix includes thermosetting resins such as phenolic resins and epoxy resins and tar,
A pitch or the like is used, but may contain cokes or various organic compounds. Of course, in the third method of the above methods, it is needless to say that at least metal silicon or silicon carbide and, if desired, boron carbide may be added and used.

Next, the fired body produced as described above, at least metal silicon or silicon carbide, and boron carbide that may be added as desired are mixed with 1100 to 140
The temperature is maintained at 0 ° C. and the furnace pressure is 0.1 to 10 hPa for 1 hour or more. The holding time may vary depending on various factors. However, the generated gas such as CO accompanying the change of the inorganic polymer or the inorganic substance into ceramics is removed from the firing atmosphere. It suffices if the time is long enough to prevent contamination. At this time, 0.1 kg / kg of the total weight of the molded body or the fired body and silicon is used.
NL (normal liter: 1200 ° C, pressure 0.1 hP
In the case of a, it is preferable to form a phase composed of a Si—SiC-based material and optionally contained boron carbide on the surface of the fired body while flowing an inert gas of 5065 liters or more. Then, temperature 1450-2500 ° C
To form an Si-SiC-based material, if necessary, by melting and impregnating silicon and / or silicon carbide and optionally boron carbide into the open pores of the fired body. Boron carbide which may be
-SiC is formed integrally with the SiC-based material phase.
A phase consisting of the base material and optionally contained boron carbide is formed. When boron carbide is not contained, the temperature for melting and impregnating is 1700 to 1800.
C is preferred.

The fired body, at least metallic silicon or silicon carbide and optionally added boron carbide were mixed with 1100
At a temperature of 1400 ° C. and a pressure of 0.1 to 10 hPa for 1 hour or more, and at that time, 0.1 NL or more, preferably 1 NL of an inert gas per 1 kg of the total weight of the fired body, metal silicon and silicon carbide. Above, more preferably 10NL
It is desirable to control so as to flow as described above. like this,
During the firing (that is, at least the stage before melting and impregnation of metallic silicon or silicon carbide and optionally added boron carbide), an inert gas atmosphere is provided to allow CO or the like accompanying the change of the inorganic polymer or inorganic substance into ceramics. The composite material obtained by melting and impregnating the above-mentioned materials such as metal silicon and silicon carbide by removing the generated gas from the firing atmosphere and preventing contamination of the firing atmosphere from the outside by O2 and the like in the atmosphere. Can be kept low.

When melting and impregnating the sintered body with metallic silicon and / or silicon carbide and optionally boron carbide, the ambient temperature is set to 1450 to 250.
Heat to 0 ° C. In this case, the firing furnace internal pressure is 0.1 to 10
The hPa range is preferred. When boron carbide is not contained, the temperature for melting and impregnating is preferably 1700 to 1800 ° C.

As described above, in combination with the coating of the carbon fiber bundle (yarn) with a flexible material such as a thermoplastic resin, and the impregnation and melting of silicon and / or silicon carbide, the fired body has the flexibility. When the material is thermally decomposed, elongated open pores remain in the gap between the yarns, and silicon and / or silicon carbide easily penetrates deep into the fired body along the elongated open pores. During this infiltration process, silicon and / or silicon carbide reacts with the carbon of the yarn to gradually carbonize from the yarn surface side, and the high oxidation resistant Si used in the present invention is used.
This will produce an impregnated composite. In addition, depending on the application, a highly oxidized Si-impregnated composite material having such a configuration is formed as a so-called highly oxidized Si-impregnated composite material layer only on a part of the surface layer of the skeleton portion made of the C / C composite. May be. Of course, a layer made of boron carbide may be formed on the outermost surface by thermal spraying.

Si—SiC forming a matrix layer
The thickness of the phase composed of the system material and optionally contained boron carbide is adjusted according to the open porosity and the pore diameter of the molded or fired body. For example, Si-SiC
When the thickness of the phase composed of the system material and optionally contained boron carbide is 0.01 to 10 mm,
The open porosity at least in the vicinity of the surface of the molded or fired body is 5 to 50%, and the average pore diameter is 1 μm or more. The open porosity of the molded or fired body is preferably 10 to 50%, and the average pore diameter is preferably 10 μm or more. If the open porosity is less than 5%, the binder in the molded body or the fired body cannot be completely removed, and if it is more than 50%, the Si-SiC-based material is impregnated and formed deep inside the skeleton, and the resistance of the composite material This is because the impact properties decrease.

In order to form the high oxidation-resistant Si-impregnated composite material layer only on the surface of the carbon fiber bundle, the open porosity at least near the surface was adjusted to be 0.1 to 30% during firing. It is preferable to use a molded body. That is, the thickness of the coating of the flexible intermediate material made of the thermally decomposable organic substance with respect to the carbon fiber bundle may be adjusted.

In order to reduce the open porosity of the molded body or the fired body from the surface toward the inside, a plurality of preformed sheets made of preformed yarns having different binder pitches are provided from the inside to the surface layer side. It is performed by arranging and molding such that the binder pitch becomes larger toward it.

When a gradient is provided in the silicon concentration in the phase composed of the above Si—SiC-based material and optionally contained boron carbide, the open porosity near the surface increases from the surface toward the inside. A composite material is manufactured using a fired body adjusted to be smaller by heating or a molded body adjusted so that the open porosity at least near the surface decreases from the surface toward the inside during firing. High oxidation resistance S
To control the porosity of the i-impregnated composite material to 10% or less,
When impregnating the fired body with at least metal silicon or silicon carbide and optionally boron carbide, the amounts of metal silicon, silicon carbide, and boron carbide are adjusted according to the open porosity of the fired body. Can be performed more easily.

In the present invention, when manufacturing a sliding material, a member for a brake or the like using the above-mentioned novel high oxidation resistant Si-impregnated composite material, the composite material manufactured as described above is subjected to surface grinding. What is necessary is just to manufacture by cutting | disconnecting to an appropriate dimension with a board etc., and carrying out surface grinding finish. In the case of a large-sized member having a specific shape, a yarn formed of a carbon fiber bundle is laminated and the like, first formed into a desired shape, and then fired to contain the Si-SiC-based material and, if desired, the material. And / or a surface of the yarn array, and a fired body is formed, and the fired body contains at least metallic silicon or silicon carbide, if desired. And boron carbide which may be impregnated and melted to form a matrix composed of a Si—SiC-based material and optionally contained boron carbide. The highly oxidation-resistant Si-impregnated composite material of the present invention can be suitably used particularly as a mold member, a sliding material, a brake member, etc., which require oxidation resistance at high temperatures.

[0052]

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. The oxidation resistance of the highly oxidation-resistant Si-impregnated composite material according to the present invention was evaluated by the following method.

(Oxidation resistance evaluation method) The oxygen concentration in the atmosphere was 10 ppm, 100 ppm, 1,000 ppm,
Prepare a series of chambers adjusted to% or 21%,
The temperature in each chamber was set at 600 ° C.
Each test sample was placed in the thus prepared chamber, and the sample was held for 100 hours in that state. 10
After a lapse of 0 hour, each sample was taken out, its weight was measured, and the weight loss rate (%) was determined by the following equation. Weight loss rate (%) = [(W1-W0) / (W0)] × 1
00 (where W1 represents the weight of the sample after being kept in the chamber for 100 hours, and W0 represents the weight of the sample before the start of the test).

(Example 1) 7 μm diameter aligned in one direction
while impregnating the bundle of m carbon fibers with phenol resin,
Bundle 12,000 carbon fibers, put this together with metal silicon, phenolic resin, a precursor of matrix carbon, and binder, put them in a tube made of thermoplastic resin, polyethylene resin, and minimize the structure of the skeleton. A unit yarn was prepared. The yarn composition at this time was composed of 40% by weight of carbon fiber, 30% by weight of a phenol resin which is a precursor of matrix carbon, and 30% by weight of metallic silicon. A prepreg sheet was woven using the series of yarns thus prepared. A required amount of a series of prepreg sheets prepared as described above is laminated, and the laminate is hot-pressed at 600 ° C. and 100 kg.
/ Cm ² . This molded body was fired at a temperature of 2,000 ° C. in a nitrogen atmosphere to obtain a C / C composite having a thickness of 20 mm. Using the obtained C / C composite,
The density measured by the Archimedes method is 1.7 g / cm
³ , and the open porosity, also measured by the Archimedes method, was 10%.

Next, the obtained C / C composite was
A purity of 99.000, consisting of an amount sufficient to give a porosity of 5%.
It was erected in a carbon crucible filled with 8% metallic silicon powder having an average particle size of 1 mm. Next, the carbon crucible was moved into the firing furnace. The temperature in the firing furnace was 1300 ° C., the flow rate of argon gas as an inert gas was 20 NL / min, the pressure in the firing furnace was 1 hPa, and the holding time was 4 hours. By raising the internal temperature to 1600 ° C., the C / C composite is impregnated with metallic silicon to obtain a highly oxidized silicon having a porosity of 5%.
An impregnated composite was produced.

When the oxidation resistance was measured using the obtained high oxidation resistance Si-impregnated composite material, the weight loss in an atmosphere containing 1% oxygen was almost 25 as shown in FIG.
%, The amount of weight loss in an atmosphere containing 1,000 ppm of oxygen is about 3%, and the amount of weight loss in an atmosphere containing 100 ppm of oxygen is extremely small and can be reduced to substantially zero. Met. The reduction at 1,000 ppm is less than about 1/10 when compared to the C / C composites tested at the same time, and also in the presence of 1% oxygen compared to the Si-impregnated composites produced by the conventional method. Was less than 1 in 2 minutes and less than 1 in 3 minutes in the presence of 1,000 ppm of oxygen. This indicates that the highly oxidation-resistant Si-impregnated composite material according to the present invention exhibits extremely excellent oxidation resistance.

(Embodiment 2) Diameter 7 μ aligned in one direction
while impregnating the bundle of m carbon fibers with phenol resin,
Bundle 12,000 carbon fibers, put this together with metal silicon, phenolic resin, a precursor of matrix carbon, and binder, put them in a tube made of thermoplastic resin, polyethylene resin, and minimize the structure of the skeleton. A unit yarn was prepared. The yarn composition at this time was composed of 40% by weight of carbon fiber, 30% by weight of a phenol resin which is a precursor of matrix carbon, and 30% by weight of metallic silicon. A prepreg sheet was woven using the series of yarns thus prepared. A required amount of a series of prepreg sheets prepared as described above is laminated, and the laminate is hot-pressed at 600 ° C. and 100 kg.
/ Cm ² . This molded body was fired at a temperature of 2,000 ° C. in a nitrogen atmosphere to obtain a C / C composite having a thickness of 20 mm. Using the obtained C / C composite,
The density measured by the Archimedes method is 1.7 g / cm
³ , and the open porosity, also measured by the Archimedes method, was 10%.

Next, the obtained C / C composite was
A purity of 99.000, consisting of an amount sufficient to give a porosity of 5%.
It was set up in a carbon crucible filled with 8%, metal silicon powder having an average particle size of 1 mm and boron carbide. Next, the carbon crucible was moved into the firing furnace. Set the temperature in the firing furnace to 1
300 ° C, 20N argon gas flow rate as inert gas
L / min, the internal pressure of the firing furnace was 1 hPa, and the holding time was 4 hours. Then, while maintaining the pressure in the firing furnace, the temperature in the furnace was raised to 1600 ° C.
The C composite was impregnated with metallic silicon and boron carbide to produce a high oxidation resistant Si-impregnated composite material having a porosity of 5%.

When the oxidation resistance was measured using the obtained high oxidation resistant Si-impregnated composite material, as shown in FIG. 3, the weight loss in an atmosphere containing 1% oxygen was almost 2%.
%, The weight loss in an atmosphere containing 1,000 ppm of oxygen is 0.3%, and the weight loss in an atmosphere containing 100 ppm of oxygen is extremely small and substantially zero. Was something. The reduction at 1,000 ppm is less than about 1/10 when compared to the C / C composites tested at the same time, and also in the presence of 1% oxygen compared to the Si-impregnated composites produced by the conventional method. Was less than 1 in 2 minutes and less than 1 in 3 minutes in the presence of 1,000 ppm of oxygen. This indicates that the highly oxidation-resistant Si-impregnated composite material according to the present invention exhibits extremely excellent oxidation resistance.

[0060]

EFFECT OF THE INVENTION The novel high oxidation resistant Si-impregnated composite material of the present invention has significantly enhanced oxidation resistance. Therefore, it can be said that it has extremely excellent properties as a member for a mold, a sliding member, and a member for a brake of a large-sized transportation engine such as an aircraft for which oxidation resistance at a high temperature is highly required. . Since it has high resistance to high temperatures, it is also suitably used as a member for molten metal used under conditions exposed to high temperatures.

[Brief description of the drawings]

FIG. 1 is a perspective view schematically showing a structure of a skeleton portion of a high oxidation resistant Si-impregnated composite material according to the present invention.

FIG. 2 is a view partially illustrating a formation state of a Si—SiC-based material in a composite member formed with a Si—SiC-based material, which is one embodiment of the highly oxidation-resistant Si-impregnated composite material according to the present invention. It is sectional drawing which shows the cross-section structure which omitted the structure.

FIG. 3 shows a decrease in weight when the oxidation resistance of a high oxidation-resistant Si-impregnated composite material formed with a Si—SiC-based material, which is one embodiment of the high oxidation-resistant Si-impregnated composite material according to the present invention, is tested. It is a figure showing a state.

[Explanation of symbols]

1A, 1B, 1C, 1D, 1E and 1F: yarn array, 2A: yarn, 2B: yarn, 3: fiber bundle (yarn), 4: silicon carbide phase, 4A: silicon carbide phase, 5: Si-
SiC-based material phase, 5A: Si-SiC-based material phase, 6: Yarn aggregate, 7: High oxidation resistant Si-impregnated composite material, 8: Matrix.

Continued on the front page F term (reference) 3J011 LA01 QA11 SA05 SD01 SD02 SE10 4G001 BA23 BA62 BA78 BA86 BB04 BB22 BB23 BB62 BB86 BC22 BC31 BC32 BC33 BC46 BC47 BC52 BC54 BC57 BD07 BD12 BD36 BE03 BE11 BE15 BE33

Claims (9)

[Claims] 1. A skeleton comprising: silicon carbide, metallic silicon, carbon substantially consisting of carbon fibers, and optionally boron carbide; and a matrix formed around the skeleton. A high oxidation resistant Si-impregnated composite material having a structure comprising: at least 50% of the silicon carbide is β-type; and the skeleton portion is formed in the carbon fiber bundle and in or around the carbon fiber bundle. It is formed of a Si-SiC-based material composed of silicon carbide and metal silicon, and boron carbide which may be contained as required. The matrix is composed of S composed of silicon carbide and metallic silicon.
The matrix and the skeleton are formed integrally with an i-SiC-based material and boron carbide that may be contained as desired, and the composite material has a porosity of 10% or less. A highly oxidation-resistant Si-impregnated composite material characterized by having: 2. The high oxidation resistant Si-impregnated composite material according to claim 1, wherein the matrix is formed along the surface of a skeleton. 3. Si-Si forming the matrix
A gradient composition in which the content ratio of silicon in the Si-SiC-based material formed in the C-based material and / or the carbon fiber bundle and / or around the carbon fiber bundle increases as the distance from the skeleton surface increases. 2. The method according to claim 1, wherein
Or the high oxidation resistant Si-impregnated composite material according to 2. 4. The skeleton portion is constituted by a carbon fiber bundle containing carbon fibers, carbon components other than carbon fibers, metallic silicon and / or silicon carbide, and optionally boron carbide. A yarn array produced by arranging at least a plurality of yarns almost two-dimensionally in parallel,
4. The molded product according to claim 1, wherein the molded product is manufactured from a formed body made of a yarn assembly that is manufactured by laminating a required number of layers so as to be orthogonal to each other. 5. High oxidation resistance Si-impregnated composite material. 5. The high oxidation resistant S
The high oxidation resistant Si-impregnated composite material according to any one of claims 1 to 4, wherein the three-dimensional network structure is formed by being continuous with each other in the i-impregnated composite material. 6. The high oxidation resistant Si-impregnated composite according to claim 1, wherein the oxygen concentration causing a 25% weight loss in a high temperature atmosphere maintained at 600 ° C. is 1% or less. material. 7. A highly acid-resistant structure comprising silicon carbide, metallic silicon, carbon substantially consisting of carbon fibers, and silica-boron oxide, and having a structure comprising a skeleton and a matrix formed around the skeleton. At least 50% of the silicon carbide is β-type, and the skeleton portion is formed of a carbon fiber bundle and silicon carbide and metal silicon formed in or around the carbon fiber bundle. And a silica-boron oxide phase integrally formed with the material. The matrix is made of silicon carbide and metal silicon.
The matrix is formed from an i-Si-based material and a silica-boron oxide phase integrally formed with the material, the matrix and the skeleton are formed integrally, and the composite material is 10 %. A highly oxidation-resistant Si-impregnated composite material having a porosity of not more than 0.1%. 8. A yarn and a yarn comprising a carbon fiber bundle in which at least either metallic silicon or silicon carbide and optionally boron carbide are added in a bundle of carbon fibers, and / or A yarn array and a yarn array, a molded article molded using a binder to which at least one material selected from metallic silicon and silicon carbide and optionally boron carbide added may be contained, or A step of calcining a molded body molded using a binder not containing any of the metal silicon, silicon carbide, and boron carbide to form a calcined body; At least one material selected from silicon carbide and boron carbide is added, and then the weight of the fired body and the total weight of metallic silicon and silicon carbide contained in the fired body While flowing the total weight 1kg per 0.1NL more inert gases, the furnace temperature 1
After holding for 1 hour or more at 100 to 1400 ° C. and a furnace pressure of 0.1 to 10 hPa, the temperature is increased to 1450 to 2500 ° C. and metal silicon and / or silicon carbide and, if desired, into the open pores of the fired body. The boron carbide that may be contained is melted and impregnated to form a Si—SiC-based material phase, and the boron carbide that is optionally contained is
-SiC is formed integrally with the SiC-based material phase.
A step of forming a matrix composed of a base material phase and, if desired, a boron carbide phase, and further comprising, if desired, further coating boron carbide on the outermost surface of the obtained fired body; silicon carbide, silicon metal , Carbon substantially consisting of carbon fiber,
And a boron oxide that may be optionally contained, a high oxidation resistant Si-impregnated composite material having a structure formed of a skeleton and a matrix formed around the skeleton, and at least silicon carbide. 50% is β-type, and the skeleton portion includes a Si-SiC-based material composed of silicon carbide and metallic silicon formed in or around the carbon fiber bundle and optionally around the carbon fiber bundle. The matrix is composed of silicon carbide and metallic silicon.
The matrix and the skeleton are formed integrally with an i-SiC-based material and boron carbide that may be contained as desired, and the composite material has a porosity of 10% or less. A method for producing a highly oxidation-resistant Si-impregnated composite material, comprising: 9. The method for producing a highly oxidation-resistant Si-impregnated composite material according to claim 8, wherein the carbon fiber bundle to be used is coated with a thermoplastic resin.