JPH05177753A - Fiber reinforced inorganic material - Google Patents

Abstract

PURPOSE:To provide a fiber reinforced inorganic material wherein stability of strength, oxidation resistance, etc., in an ultra-high temperature state can be obtained for a long time and its reliability is high. CONSTITUTION:Fiber reinforced layers A, B composed by enclosing a carbon fiber 1 with a parent material texture 2 are laminated. Oxidation preventive layers C, D are formed respectively between the adjacent fiber reinforced layers A, B and on a surface layer of the fiber reinforced layer B of the most outside layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber reinforced inorganic material, and more particularly to a technique for obtaining high strength, high toughness and environmental stability under high temperature conditions.

[0002]

2. Description of the Related Art Aircraft, rocket, space, nuclear fusion, rocket jet ramjet engine in the technical fields that require high temperature, high strength, high toughness and environmental stability, As a material for an ultrahigh temperature heat resistant wall, a fiber reinforced inorganic material that is an ultraheat resistant material capable of withstanding an ultrahigh temperature in the range of about 1000 to 2000 ° C is required. Although it is difficult to provide a material that completely satisfies such uses, a heat-resistant composite material in which a heat-resistant and oxidation-resistant base material texture layer is attached to the surface of carbon-based fiber as a material that partially satisfies Etc. are being considered.

The heat-resistant composite material conventionally provided is formed into a desired shape of a fiber molded body in which a plurality of single fibers are aggregated, and the fiber molded body is subjected to a CVD method (
It is obtained by depositing a base material texture layer by a chemical vapor deposition method or the like. When the monofilament of the fiber molded body is a carbon fiber, that is, when the base material structure layer is a carbon-based material, it easily oxidizes in a high temperature environment, and the stability to the environment such as oxidation resistance is impaired. Therefore, an antioxidant layer having a thickness of about 100 to 200 μm is applied to the surface layer of the base material structure layer surrounding the fiber molded body.

[0004]

However, when cracking or chipping due to repeated load or the like occurs in the antioxidant layer formed on the surface layer of the base material structure layer, rapid oxidation is likely to occur in a high temperature environment, The stability of the oxidation resistance with respect to the environment will be significantly impaired, and the structural strength of the heat resistant composite material will be significantly reduced. Therefore, since stability such as strength and oxidation resistance in a high temperature state cannot be obtained, such a heat resistant composite material could not be used for a long time or in an application requiring reliability.

The present invention has been proposed in view of the above circumstances, and provides a fiber-reinforced inorganic material that can obtain stability such as strength and oxidation resistance in an ultrahigh temperature state for a long time and has high reliability. The purpose is to provide.

[0006]

Therefore, the fiber-reinforced inorganic material according to the invention of claim 1 is formed by laminating a fiber-reinforced layer composed of carbon fibers surrounded by a matrix structure, and adhering to adjacent fiber-reinforced layers and The formation of an antioxidant layer on each of the outer layers of the fiber-reinforced layer was the solution.

It is desirable that at least one of the fiber-reinforced layers has a cross-sectional area that does not cause immediate fracture. Further, it is desirable that the antioxidant layer be composed of a metal oxide polymer and an inorganic filler. Further, it is preferable that the fiber reinforced layer has a deformation-permissible layer integrally formed on the surface of the carbon fiber and made of carbon or boron nitride having a low shear strength. The base material structure is selected from silicon carbide or nitride, boron carbide, carbides, nitrides, borides, and silicides of Group IVb / Vb / VIb metals in the Periodic Table of the Elements. In some cases, the main component is the one obtained.

[0008]

According to the first aspect of the present invention, even if the outermost antioxidant layer is cracked or chipped due to repeated loading under a high temperature environment, the innermost fiber-reinforced layer is the inner layer. The anti-oxidation layer prevents the oxidation and maintains the stability of the oxidation resistance to the environment. Therefore, the structural strength of the material is maintained without lowering. In addition, by laminating the fiber reinforced layers, the structural strength against the above repeated load or the like is borne by each fiber reinforced layer, and the stress is dispersed. Therefore, stability such as strength and oxidation resistance in an ultrahigh temperature state can be obtained, and the material can be used as a long-life and highly reliable material in the ultrahigh temperature state.

According to the second aspect of the present invention, since at least one of the fiber reinforced layers is provided with a cross-sectional area that does not cause immediate fracture, stability such as strength in an ultrahigh temperature state can be obtained.

Further, in the invention according to claim 3, the deformation-permissible layer formed on the surface of the carbon fiber, when a deformation force is applied to the fiber-reinforced inorganic material which is a composite material,
By having plastic deformability, relative displacement between the carbon fiber and the base material structure layer is allowed. Therefore, the strength of the composite material is improved by utilizing the original strength of the carbon fiber, and the oxidation resistance and the like based on the characteristics of the base material structure layer are obtained.

Further, in the invention according to claim 4, the base material composition is a composition other than carbon-based, that is, silicon carbide or nitride, boron carbide, specific metal carbide, nitride,
When it is formed of a material whose main component is selected from boride, silicide, etc., due to the existence of the deformation-permissible layer, the relationship with the carbon fiber is reduced, and the base metal structure layer is essentially Oxidation resistance and the like at high temperature is imparted.

Further, in the invention according to claim 5, the base metal structure is a carbide or nitride of silicon, a carbide of boron, a carbide or a nitride of IVb group, Vb group or VIb group metal in the periodic table of elements. Since the main component is selected from the group consisting of boron, boride, and silicide, it is possible to reduce the involvement with carbon fiber based on the existence of the deformation-permissible layer, and in the original high temperature state of the base metal structure. Oxidation resistance and the like are imparted.

[0013]

EXAMPLE An example of the fiber-reinforced inorganic material according to the present invention will be described below with reference to FIG. In FIG. 1, symbols A and B indicate fiber reinforced layers, and symbols C and D indicate antioxidant layers.

In the fiber-reinforced inorganic material of this embodiment, a fiber-reinforced layer B having a cross-sectional area such that it does not immediately break as a structural material is laminated with a fiber-reinforced layer B above and below the fiber-reinforced layer A and each fiber-reinforced layer. And an anti-oxidation layer C between B and
The outermost fiber-reinforced layer B is provided with an antioxidant layer D on its surface.

The fiber reinforced layers A and B are each composed of a carbon fiber 1 and a matrix material 2 surrounding the carbon fiber 1. The former carbon fiber 1 is a reinforced fiber as a composite material, and is obtained by assembling a plurality of single fibers 1a in a two-dimensional direction and performing a molding process as necessary. The reason for using the carbon fiber 1 is that it has excellent tensile strength in a temperature range up to a high temperature in a non-oxidizing atmosphere.

A deformation permitting layer 3 is integrally formed on the surface of the carbon fiber 1. The deformation permitting layer 3 is made of carbon or boron nitride. As the carbon or boron nitride, those having a hexagonal crystal structure are applied. Carbon or boron nitride is applied because it does not react with the carbon fiber 1 and is compatible with the carbon fiber 1 in a stable state and has plastic deformability. Then, the deformation-permissible layer 3 has a thickness corresponding to the thickness of the base material structure 2 around it.
It is set to 10% or more and 60% or less. The reason for this is 10%
In the following, the original strength of carbon fiber 1 cannot be exhibited and 60%
This is because if it is above, the oxidation resistance is reduced.

The base material structure 2 is required to be a material that does not react with carbon or boron nitride, is stable and compatible, and has high oxidation resistance. Is selected. Silicon carbide or nitride, boron carbide, IVb group / Vb group in the periodic table of elements
VIb group metals Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W
Carbides, nitrides, borides and silicides of.

The antioxidant layers C and D are composed of a metal oxide polymer and an inorganic filler, and form a ceramic film on the surface layer of each of the fiber reinforced layers A and B by drying at room temperature or heating at low temperature. By doing so, you can get it. Examples of the metal oxide-based polymer include alkali metal, organoalkoxy metal, alkoxy metal, modified acetylacetonate metal and the like. By coating the surface layers of the fiber-reinforced layers A and B with the antioxidant layers C and D, a coating film having excellent weather resistance, heat resistance, corrosion resistance, antifouling property, etc. can be obtained.

According to this embodiment, 1000 ° C. to 2000 ° C.
Even if the outermost antioxidant layer D is cracked or chipped due to repeated loading under an ultrahigh temperature environment of about 0 ° C., the innermost antioxidant layer C prevents the innermost fiber reinforced layer A from being broken.
Can be prevented, and the stability of the oxidation resistance to the environment can be maintained. Since the innermost fiber-reinforced layer A is provided with a cross-sectional area that does not cause immediate fracture, the structural strength can be maintained without lowering the structural strength of the present material. In addition, by forming the fiber-reinforced layers A and B in a three-layer structure, the structural strength against the repeated load or the like can be applied to the fiber-reinforced layers A and B to disperse the stress.

Further, since the deformation allowance layer 3 is formed on the surface of the carbon fiber 1, the deformation allowance layer 3 should have plastic deformability when a deformation force is applied to the fiber reinforced inorganic material which is a composite material. Thus, the relative displacement between the carbon fiber 1 and the base material structure 2 can be allowed. This makes it possible to improve the strength of the composite material by taking advantage of the original strength of the carbon fiber, and to obtain the oxidation resistance and the like based on the characteristics of the base material structure 2.

Further, the base material structure 2 has a composition other than carbon, that is, one selected from silicon carbide or nitride, boron carbide, specific metal carbide, nitride, boride, silicide and the like. If it is formed of the main component, it is possible to reduce the relation with the carbon fiber 1 due to the existence of the deformation-permissible layer 3, and to improve the oxidation resistance of the base material structure 2 in the original high temperature state. Can be given.

[0022]

As described in detail above, the fiber-reinforced inorganic material according to the present invention is formed by laminating a fiber-reinforced layer having carbon fibers and a matrix structure with an antioxidant layer interposed therebetween. Since the antioxidant layer is formed on the surface of the outermost fiber reinforced layer, even if the outermost antioxidant layer is cracked or chipped in an ultrahigh temperature environment, the inner layer is protected against oxidation. The layer can prevent oxidation of the innermost fiber-reinforced layer and maintain the stability of the oxidation resistance to the environment. Therefore, it is possible to prevent the structural strength of the material from lowering. Further, by laminating the fiber reinforced layers, the structural strength can be applied to each fiber reinforced layer, and the stress can be dispersed. Therefore, it is possible to obtain stability such as strength and oxidation resistance in an ultrahigh temperature state, and it is possible to use the material as a material having a long life and high reliability in the ultrahigh temperature state.

[Brief description of drawings]

FIG. 1 is a front sectional view showing a structural model of a fiber-reinforced inorganic material according to the present invention.

[Explanation of Codes] 1 carbon fiber 2 matrix structure 3 deformation allowable layer A fiber reinforced layer B fiber reinforced layer C antioxidant layer D antioxidant layer

Claims (5)

[Claims] 1. A fiber-reinforced layer comprising carbon fibers surrounded by a matrix structure is laminated, and an antioxidant layer is formed on each of the adjacent fiber-reinforced layers and the outermost layer of the fiber-reinforced layer. Fiber reinforced inorganic material to be used. 2. The fiber-reinforced inorganic material according to claim 1, wherein at least one of the fiber-reinforced layers is provided with a cross-sectional area that does not cause immediate fracture. 3. The fiber-reinforced inorganic material according to claim 1, wherein the antioxidant layer is composed of a metal oxide polymer and an inorganic filler. 4. The fiber-reinforced layer has a deformation-permitting layer which is integrally formed on the surface of the carbon fiber and is made of carbon or boron nitride having a low shear strength. The fiber-reinforced inorganic material described. 5. The base metal structure is a silicon carbide or nitride, a boron carbide, or a group IVb group in the periodic table of elements.
The fiber-reinforced inorganic material according to claim 3, characterized in that a main component is selected from the group consisting of carbides, nitrides, borides, and silicides of Vb group / VIb group metals.