JPH09286672A - Ceramic composite material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a ceramic composite material less liable to the deterioration of mechanical characteristics at the time of practical use at a high temp. even in an environment in which oxygen and steam exist, e.g. in the air. SOLUTION: Plural inorg. fibers each having a surface layer positioned on the surface of the fiber body and different from the fiber body in structure are mixed with ceramics to obtain the objective ceramic composite material consisting of the inorg. fibers and a matrix made of the ceramics positioned around the fibers and having self-restorable interfacial layers formed between the fibers and the matrix by the reaction of the surface layers with the ceramics.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic composite material, and more particularly to a ceramic composite material having excellent heat resistance, corrosion resistance and mechanical properties.

[0002]

2. Description of the Related Art Conventionally, various materials having excellent heat resistance and mechanical properties have been developed as materials used in the fields of space and aviation, etc. Composite materials have been proposed.

In particular, in recent years, it has been required for the above ceramic composite materials to have excellent physical properties such as mechanical strength and fracture toughness, and in order to bring such physical properties to the required levels, fibers and a matrix are required. It is important to form an interfacial layer between and. That is, it is necessary to form an interface layer between the fiber and the matrix in order to adjust the bond strength between the fiber and the matrix, the difference in the thermophysical properties between the fiber and the matrix, and the difference in elastic modulus. Proposed [“Acta metall., Vol.
34, No.12, p.2435 (1986). ”,“ Ceramic Bulletin, V
ol.68, No.2, p.395 (1989). ”,“ Ceramic Bulletin,
Vol.68, No.2, p.429 (1989). ”,“ J. Am. Ceram. S
oc., Vol.73, No.6, p.1691 (1990). ”,“ Composites,
Vol.21, No.4, p.305 (1990). ”].

Conventionally, a carbon interface layer or a boron nitride interface layer has been proposed as the interface layer, and Si or C coated with carbon or boron nitride by a chemical vapor deposition method.
Fiber [registered trademark of "Hynicalon", Nippon Carbon Co., Ltd.
Manufactured], Si-C-O fiber [registered trademark of "Nicalon", manufactured by Nippon Carbon Co., Ltd.], SiC fiber [registered trademark of "SCS fiber" manufactured by Textron, Inc. of the United States], or has a carbon layer on the outermost surface of the fiber. By using Si-Ti-C-O fiber ["Tyranno fiber (TM-S5, TY-F1)" registered trademark, manufactured by Ube Industries, Ltd.] as the inorganic fiber, the fibers and matrix in the ceramic composite material are formed. Are formed between. The carbon interface layer and the boron nitride interface layer suppress the reaction between the inorganic fiber and the matrix at a high temperature in an atmosphere free of oxygen and water vapor, and thus the composite material having the carbon interface layer and the boron nitride layer. Is known to exhibit excellent mechanical properties in the temperature range from room temperature to relatively high temperatures [“Ceram. Eng. Sc.
i., Proc., Vol.5, (7-8), p.513 (1984). ”,“ Glasse
s and Glass-Ceramics; MH Lewis, Ed .; Chapman and H
all: London, 1989; p.336. ”,“ Proc. 4th Int. Symp
o. Ultra-high Temp. Mater. '94 in Tajimi, Nov.30-D
ec.1, Tajimi (1994), p.86. ”].

However, the carbon forming the carbon interface layer reacts with oxygen at 600 ° C. or higher [Encyclopedia of Science and Chemistry, published by Iwanami Shoten], and the boron nitride forming the boron nitride interface layer reacts with oxygen at 900 ° C. or higher. Shi (Advanced
New development of ceramics, issued by Toray Research Center],
Further, in the presence of water vapor, they are easily decomposed at the temperatures below these [Chemical Encyclopedia, published by Kyoritsu Shuppan]. Therefore, in an environment such as the atmosphere where oxygen and water vapor exist, the carbon interface layer or the boron nitride interface layer is destroyed by the oxidation or decomposition of carbon or boron nitride during actual use at high temperature, and as a result, the composite material It has a problem that mechanical properties are impaired (deteriorated with time) [“Glasses and Glass-Ceramics; MHLewis, Ed .; Ch
apman and Hall: London, 1989; p.336. ”,“ Proc. 4t
h Int. Sympo. Ultra-high Temp. Mater. '94 in Tajim
i; Nov.30-Dec.1, Tajimi (1994), p.86. ”,“ Proc.
1993 Powder Metallurgy World Congress; Y. Bando and
K. Kosuge, Eds .; July, 12-15, Kyoto (1993), p.86.
”、“ Scripta Metallurgica et Materialia, Vol.31,
No.8, p.959 (1994). ”].

Therefore, an object of the present invention is to provide a ceramics composite material which is less likely to deteriorate in mechanical properties during actual use at high temperature even in an environment where oxygen and water vapor exist, such as in the atmosphere. is there.

[0007]

As a result of various studies to solve the above problems, the present inventors have made a ceramic composite material in which an interfacial layer having self-repairing property is formed between a fiber and a matrix. However, it has been found that the above-mentioned object can be achieved.

The present invention has been made based on the above findings, and a plurality of inorganic fibers having a fiber body and a surface layer located on the surface of the fiber body and having a structure different from that of the fiber body, and It is made of ceramics, the fiber portion made of the inorganic fiber, made of the ceramics,
A self-healing interface layer formed between the fiber portion and the matrix portion by reacting the surface layer with the ceramics, and a matrix portion around the fiber portion; A characteristic ceramic composite material is provided.

Further, in the present invention, the interface layer has a thickness of 3 nm or more, and (g) is an amorphous material consisting essentially of Si, Ti and / or Zr, and C and O. h) a crystalline aggregate of the above amorphous and β-SiC of 1000 nm or less, TiC and / or ZrC, and (i) the above crystalline: and SiOx existing in the vicinity thereof
And TiOx and / or ZrOx (0 <x ≦ 2), and the average elemental composition thereof is 0.5 to 50 wt% for Si and 0 for Ti and / or Zr. .05 to 20 wt%, C is 30 to 99.0 wt%, O
The above ceramic composite material is 0.001 to 40 wt%.

According to the present invention, the interface layer has a thickness of 3 nm or more, and (j) is substantially Si, C, and O.
And (n) the above amorphous and 1000n
m or less β-SiC crystalline, (l) the amorphous and crystalline, or (m) the amorphous and / or crystalline and a mixed system of carbon aggregates, and The average composition of Si is 0.1 to 75 wt% and C is 25 to 99.
The present invention provides the above ceramic composite material containing 5 wt% and O of 0.001 to 30 wt%.

According to the present invention, the structure of the fiber body is
The following structure, the structure of the surface layer is the following structure (A)
Alternatively, the above ceramic composite material which is (B) is provided. .

Structure: (a) Substantially Si, Ti and / or Zr, C and O
And (b) the above amorphous and 1000n
A crystalline aggregate of β-SiC of m or less and TiC and / or ZrC, or (c) SiOx existing in the above crystalline and its vicinity, TiOx and / or ZrOx.
(0 <x ≦ 2), which is an amorphous mixed system and has an average elemental composition of 30 to 80 wt% Si and Ti.
And / or Zr is 0.05 to 8 wt% and C is 15 to 69.
A structure in which wt% and O are 0.01 to 20.0 wt%.

Structure (A): Si continuously or stepwise changes from 0.5 to 20 wt% to the average composition value of the inorganic fiber, and C continuously from 80 to 99.5 wt% to the average composition value of the inorganic fiber. Change from 0 to 19.
It changes continuously or stepwise from 5 wt% to the average composition value of the inorganic fiber, and Ti and / or Zr is 0 to 1
Structure containing 0 wt%.

Structure (B): Si from 20 to 80 wt% to 0
To 60 wt% continuously or stepwise, C changes from 0 to 50 wt% to 40 to 100 wt% continuously or stepwise, and O changes from 2 to 80 wt% to 0 to 45
It changes continuously or stepwise up to wt%, and T
It has a structure containing 0 to 10 wt% of i and / or Zr as the outermost layer, and Si continuously or stepwise changes from 0 to 60 wt% to the average composition value of the inorganic fiber, and C is 40 to 100 wt%. From 0 to 45 wt% and the average composition value of the inorganic fiber is continuously or stepwise changed from 0 to 45 wt% to the average composition value of the inorganic fiber, and Ti and / or Zr is 0 to 10 wt%. % Structure containing as a second layer.

In the present invention, the structure of the fiber body is
The following structure, the structure of the surface layer is the following structure (C)
Alternatively, the above ceramic composite material of (D) is provided. .

Structure: (d) An amorphous material consisting essentially of Si, C, and O,
(E) a crystalline aggregate of β-SiC of 1000 nm or less, amorphous SiO ₂ and / or substantially Si, and C,
O is an aggregate with an amorphous material, or (f) is a mixed system of the above-mentioned amorphous material and / or the above aggregate, and an aggregate of carbon, and the average elemental composition thereof is that Si is 30 to 30%. 80w
t%, C 10 to 65 wt%, O 0.01 to 25 wt
%, H is 2 wt% or less.

Structure (C): Si continuously or stepwise changes from 0.5 to 20 wt% to the average composition value of the inorganic fiber, and C continuously or from 75 to 99 wt% to the average composition value of the inorganic fiber. It changes in stages and O is 0-24.5w
A structure that continuously or stepwise changes from t% to the average composition value of the inorganic fiber.

Structure (D): Si 20 to 80 wt% to 0
To 55 wt% continuously or stepwise, C continuously changes from 0 to 55 wt% to 45 to 100 wt% continuously or stepwise, and O changes from 2 to 80 wt% to 0 to 2
The outermost layer has a structure that continuously or stepwise changes up to 4.5 wt%, and Si changes continuously or stepwise from 0 to 55 wt% to the average composition value of the inorganic fiber, and C is 45 to 100 wt. % To the average composition value of the inorganic fiber continuously or stepwise, and O is 0 to 24.5.
A structure having as a second layer a structure that continuously or stepwise changes from wt% to the average composition value of the inorganic fiber.

In the present invention, the surface layer has a thickness of 1
The above ceramic composite material having a thickness of 0 nm or more is provided.

The present invention also provides the above-mentioned ceramic composite material, wherein the above-mentioned ceramic is one or more selected from the group consisting of carbide, nitride, boride, silicide and oxide.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION The ceramic composite material of the present invention will be described in more detail below. The ceramic composite material of the present invention is formed of a plurality of inorganic fibers having a fiber body and a surface layer located on the surface of the fiber body and having a different structure from the fiber body, and ceramics.

In the present invention, the above-mentioned "surface layer" means a coating film formed by coating the surface of a fiber (fiber as a raw material) with a film by a known physical or chemical method, and It includes both of the surface portion when the fiber is treated to change the structure of the surface portion from the structure of the fiber body to form a structure different from the internal structure (structure of the fiber body) on the surface portion of the fiber.

In the present invention, as the above-mentioned fiber used as a raw material for the above-mentioned inorganic fiber, a fiber having the following structure or a fiber having the following structure is preferably used. That is, as described above, since the structure of the fiber is the same as the structure of the fiber main body in the inorganic fiber, the following structures and are also specific examples of the fiber main body. Structure; (a) Substantially Si, Ti and / or Zr, C and O
And (b) the above amorphous and 1000n
A crystalline aggregate of β-SiC of m or less and TiC and / or ZrC, or (c) the above crystalline, and SiOx existing in the vicinity thereof, TiOx and / or ZrO.
x (0 <x ≦ 2), which is an amorphous mixed system, and has an average elemental composition of 30 to 80 wt% Si and T
i and / or Zr is 0.05 to 8 wt% and C is 15 to 6
9 wt%, O is 0.01-20.0 wt% structure.

Structure: (d) An amorphous material consisting essentially of Si, C, and O,
(E) a crystalline aggregate of β-SiC of 1000 nm or less, amorphous SiO ₂ and / or substantially Si, and C
And an amorphous aggregate of O, or (f) a mixed system of the above amorphous and / or aggregate and a carbon aggregate, and the average elemental composition of which is Si. Is 30 ~
80 wt%, C 10-65 wt%, O 0.01-2
5 wt%, H is 2 wt% or less, preferably 0 to 0.5 w
Structure that is t%.

Here, the "vicinity thereof" in the above-mentioned structure (c) is preferably a region where the distance from the crystalline particles is 100 nm or less.

As the above fiber, Si which is commercially available from Ube Industries, Ltd. as "Tyranno fiber" (registered trademark)
-Ti or Zr-C-O inorganic fiber, or Si-C-O inorganic fiber commercially available as "Nicalon" (registered trademark) or "Hinicalon" (registered trademark) from Nippon Carbon Co., Ltd. It is also possible to use a commercially available product.

In the inorganic fiber, the surface layer formed on the surface of the fiber body (including both the circumferential surface and the end surface) is a film on the surface of the fiber as a raw material as described above. It includes both a coating film obtained by coating the above and a film in which the structure of the surface portion of the fiber is changed. That is, the surface layer has a structure different from that of the fiber main body having the structure of the fiber as it is, and if the surface layer has the different structure, the composition of each component and the crystal structure (crystalline structure) The structure of the surface layer is, for example, the following structures (A) to (D).

Structure (A): Si changes continuously or stepwise from 0.5 to 20 wt% to the average composition value of the inorganic fiber (meaning the elemental composition value shown in the above-mentioned structure and), and C is 80. .About.99.5 wt% to the average composition value of the inorganic fiber continuously or stepwise, and O is 0 to 19.
It changes continuously or stepwise from 5 wt% to the average composition value of the inorganic fiber, and Ti and / or Zr is 0 to 1
Structure containing 0 wt%.

Structure (B): Si from 20 to 80 wt% to 0
To 60 wt% continuously or stepwise, C changes from 0 to 50 wt% to 40 to 100 wt% continuously or stepwise, and O changes from 2 to 80 wt% to 0 to 45
It changes continuously or stepwise up to wt%, and T
It has a structure containing 0 to 10 wt% of i and / or Zr as the outermost layer, and Si continuously or stepwise changes from 0 to 60 wt% to the average composition value of the inorganic fiber, and C is 40 to 100 wt%. From 0 to 45 wt% and the average composition value of the inorganic fiber is continuously or stepwise changed from 0 to 45 wt% to the average composition value of the inorganic fiber, and Ti and / or Zr is 0 to 10 wt%. % The structure having the contained structure as the second layer (the innermost layer of the outermost layer).

Structure (C): Si continuously or stepwise changes from 0.5 to 20 wt% to the average composition value of the inorganic fibers, and C continuously or stepwise from 75 to 99 wt% to the average composition value of the inorganic fibers. It changes in stages and O is 0-24.5w
A structure having a structure that continuously or stepwise changes from t% to the average composition value of the inorganic fiber.

Structure (D): Si 20 to 80 wt% to 0
To 55 wt% continuously or stepwise, C continuously changes from 0 to 55 wt% to 45 to 100 wt% continuously or stepwise, and O changes from 2 to 80 wt% to 0 to 2
The outermost layer has a structure that continuously or stepwise changes up to 4.5 wt%, and Si changes continuously or stepwise from 0 to 55 wt% to the average composition value of the inorganic fiber, and C is 45 to 100 wt. % To the average composition value of the inorganic fiber continuously or stepwise, and O is 0 to 24.5.
A structure having as a second layer a structure that continuously or stepwise changes from wt% to the average composition value of the inorganic fiber.

In the above structures (A) to (D), "continuous"
Means that the composition of each element in the thickness direction of the surface layer gradually changes, and the composition value of each component is substantially continuous as shown in FIG. 1, for example. Also, "gradual"
Means that the surface layer is divided into a plurality of regions in which the composition values of each component are substantially continuous, and between each region, the composition of each element changes rapidly and the composition value is substantially Shows the state of not being continuous (changing discontinuously between each region). Further, the above-mentioned "continuous or stepwise change" means a random change. Therefore, as shown in FIG. 1, the above-mentioned "change" occurs when the composition of each component increases or decreases individually. Further, the crystal structure also changes randomly, and crystalline and amorphous are randomly mixed.

Here, when the fiber having the above structure is used as a raw material, the surface layer having the above structure (A) or (B) is preferably formed, and the fiber having the above structure is used as a raw material. In the case of the above structure (C) or
A surface layer having (D) is preferably formed. Therefore,
As the inorganic fiber used in the present invention, those composed of a fiber body having the above structure and a surface layer having the structure (A) or (B) formed on the surface of the fiber body, and the above structure. Those comprising a fiber main body having and a surface layer having the above-mentioned structure (C) or (D) formed on the surface of the fiber main body are preferably used, and when used, they may be used alone or in combination. You can
Further, the thickness of the surface layer is preferably 10 nm or more, and more preferably 10 to 5000 nm.

The fiber diameter of the inorganic fiber is 0.1 to
Preferably it is 1000 μm.

The above-mentioned inorganic fibers can be obtained by the following method (a).
It is easily obtained by surface-treating the above fiber by (d)
be able to. Method (a); known chemical vapor deposition method (chemical vapor deposition method, hereinafter
The “CVD method”) is applied to the surface of the fiber to
So that the surface layer (coating film) of the structure of
A method of coating while changing the composition step by step. this
The raw material used at this time is Si (C_mH_{2m + 1})_nCl
_4-n(N = 0-4, m = 1-6), SiH_nCl
_4-n(N = 0-4), Si (C_mH_{2m + 1})_nH_4-n (N =
0-4, m = 1-6), TiCl_Four, ZrCl_Four, C_n
H_{n + 2}, C₆H₆ , H_Two, NO_Two, H_TwoO, CO_Two, O
_TwoEtc. can be preferably used.

Method (b); known physical vapor deposition method (hereinafter
By "PVD method"), coating is performed on the surface of the fiber while changing the composition continuously or stepwise so that a surface layer (coating film) having the above-mentioned structure is formed. The target used in this case is preferably an amorphous or crystalline material prepared with the same composition as the above-mentioned surface layer, or a mixture thereof. Further, this target may be either one sintered after mixing the inorganic powder, one inorganicized the organometallic compound, and one mineralized the mixture of the inorganic powder and the organometallic compound, and further this target You may prepare itself by said CVD method or PVD method.

Method (c): The above fibers were mixed with CO, CO ₂ ,
_{Si (C m H 2m + 1} ) n Cl 4-n (n = 0~4, m = 1~
_{6), Si (C m H} 2m + 1) n H 4-n (n = 0~4, m = 1
_{~6), H 2, C n} H n + 2, C 6 H 6, SiO, Ar,
At least 1 selected from the group consisting of He and N ₂ etc.
1000 ° C in an atmosphere of more than one gas or vapor
A method of forming the surface layer on the surface by heat treatment at 1800 ° C. to change the surface structure of the fiber.

Method (d); 600 g of the above-mentioned fiber was previously placed in an atmosphere in which oxygen or a compound containing oxygen was present.
° C. to 1500 was heat-treated at ° C. After introduction of oxygen near the surface of the _{fibers, CO, CO 2, Si (} C m H 2m + 1) n Cl
_4-n (n = 0 to 4, m = 1 to 6), Si (C _m H _{2m + 1} ) _n
H _4-n (n = 0 to 4, m = 1 to 6), H ₂ , C _n H _{n + 2} ,
The structure of the surface portion of the fiber is heat-treated at 1000 ° C. to 1800 ° C. in an atmosphere of at least one gas or vapor selected from the group consisting of C ₆ H ₆ , SiO, Ar, He and N _2. A method of forming the above surface layer by changing.

The above methods (a) to (d) may be carried out continuously when the fiber is produced. Further, the inorganic fiber is obtained by appropriately performing the above methods (a) to (d), and in particular, the above methods (a) and (b) are not limited to the above structures (A) to (D). In the surface layer having a), it is preferable to obtain a composition in which the composition of each component changes stepwise, and the above methods (c) and (d) are surface layers having the structures (A) to (D). In, it is suitable for obtaining a composition in which the composition of each component changes continuously.

Further, in the present invention, the above-mentioned inorganic fibers can be used in various known forms. Specifically, it may be continuous fibers or short fibers obtained by cutting continuous fibers, and plain weave, satin weave, multiaxial weave, three-dimensional weave woven from continuous fibers or a sheet obtained by aligning continuous fibers in one direction. It may be in the form of a substance or a mixture of two or more of these.

The ceramics used in the present invention include one or more ceramics selected from the group consisting of crystalline or amorphous oxides, carbides, nitrides, borides and silicides, and these ceramics. Examples of the ceramic material in which the particle dispersion is strengthened are as follows.

Specific examples of the above oxides include aluminum, magnesium, silicon, yttrium, calcium, titanium, zirconium, niobium, iron, copper, barium, zinc, strontium, beryllium, indium,
Examples thereof include oxides of elements such as uranium, tantalum, neodymium, scandium, ruthenium, rhodium, tin, nickel, cobalt, molybdenum, manganese, germanium, lead and hafnium, and composite oxides thereof. Also,
In addition to the above-mentioned amorphous oxides, examples of amorphous oxides include silicate glass, phosphate glass, and borate glass. Further, as the mixed oxide and crystalline oxide ceramics, crystallized glass (glass ceramics) can be mentioned in addition to the above-exemplified mixture of oxides. As a specific example of crystallized glass, the main crystal phase is β-Sp
It is a _{odumene LiO 2 -Al 2 O 3 -MgO} -SiO
_2- based crystallized glass and LiO ₂ —Al ₂ O ₃ —MgO—
SiO ₂ —Nb ₂ O ₅ type crystallized glass, the main crystal phase is Cord
_{Ba MgO-Al 2 O 3 -SiO} 2 based crystallized glass which is Ierite, the main crystal phase is a Mullite or Celsian
O-Al ₂ O ₃ -SiO ₂ based crystallized glass, the main crystalline phase
Anorthite such as CaO—Al ₂ O ₃ —SiO ₂ type crystallized glass may be used.

Specific examples of the above-mentioned carbides include silicon, titanium, zirconium, aluminum, uranium, tungsten, tantalum, hafnium, boron, iron, manganese,
Examples thereof include carbides of elements such as molybdenum and complex carbides thereof. Specific examples of the above-mentioned nitride include nitrides of elements such as silicon, titanium, zirconium, aluminum, magnesium, hafnium, boron and molybdenum, composite nitrides of these, and sialon. Specific examples of the boride include boride of elements such as titanium, yttrium and lanthanum, CeCo ₃ B ₂ and CeCo ₄ B.
₄ , and lanthanoids of platinum group boride such as ErRh ₄ B ₄ are included. Specific examples of the silicide include silicides of elements such as molybdenum, nickel and niobium.

Further, as the above-mentioned ceramics, solid solutions of the above-exemplified various ceramics can be used.

Specific examples of the above ceramic material are selected from silicon nitride, silicon carbide, zirconium oxide, magnesium oxide, aluminum oxide, potassium titanate, magnesium borate, zinc oxide, titanium boride and mullite. A ceramic material in which spherical particles, polyhedral particles, plate-shaped particles and / or rod-shaped particles of at least one kind of inorganic material are uniformly dispersed in ceramics such as the above oxides in an amount of 0.1 to 60 vol% can be mentioned. It is preferable that the spherical particles and the polyhedral particles have a particle diameter of 0.1 μm to 1 mm, and the plate-like particles and the rod-like particles have an aspect ratio of 1.5 to 1000.

The ceramic composite material of the present invention comprises a fiber portion made of the above-mentioned inorganic fibers, a matrix portion made of the above-mentioned ceramics and located around the fiber portions, and the above-mentioned inorganic fibers react with the above-mentioned ceramics, The self-repairing interface layer is formed between the fiber portion and the matrix portion.

The fiber portion is a portion formed by the inorganic fiber (the portion where the surface layer is not formed). The shape of the fiber portion corresponds to the shape in which the inorganic fibers are arranged. When the above inorganic fibers are used as a plain woven sheet and a plurality of the sheets are arranged at predetermined intervals, a plurality of plain woven fiber portions are formed. Further, the amount of the above fiber portion is preferably 5 to 85 vol% with respect to the entire ceramic composite material.

The matrix portion is located around the fiber portions, that is, in the case where the fiber portions are plain-woven and arranged in plurals, located around the fiber portions and between the inorganic fibers, and the ceramic composite is formed. This is the part that forms the outer shape of the material. The amount of the matrix portion is 14.5 to 94.5 vo with respect to the whole ceramic composite material.
It is preferably 1%.

The above-mentioned interface layer included in the ceramic composite material of the present invention has a self-repairing property. here,
The "self-healing property" means that, when the ceramic composite material of the present invention is used, for example, at least a part of the interface layer is oxidized by an oxidation reaction and an oxide is formed inside the interface layer. When the oxide reacts with the interface layer to restore the interface layer, or when an oxide is formed around the interface layer, the oxide reacts with the inorganic fiber or the ceramic. And the function of forming a new interface layer having the same composition and structure as the interface layer.

As the above interface layer, the following interface layers (1) and
(2) etc. are mentioned. Interface layer (1); thickness of 3 nm or more, preferably 3 to 6000
nm, and (g) substantially Si, Ti and / or Z
r, an amorphous material composed of C and O, (h) the above amorphous material and a crystalline aggregate of β-SiC of 1000 nm or less, TiC and / or ZrC, and C, or (i) the above Crystalline: and SiOx and TiO existing in the vicinity thereof
x and / or ZrOx (0 <x ≦ 2) is an amorphous mixed system having an average composition of Si of 0.5 to 50.
wt%, Ti and / or Zr is 0.05 to 20 wt%,
C is 30 to 99.0 wt%, O is 0.001 to 40 wt%
The interface layer, which is%.

Interface layer (2); thickness of 3 nm or more, preferably 3 to 6000 nm, (j) substantially Si and C
And (a) an amorphous material including O, (k) the amorphous material, and 100
A mixed system of 0-nm or less β-SiC crystalline, (l) the amorphous and crystalline, or (m) the amorphous and / or crystalline, and a carbon aggregate. The average composition of Si is 0.1 to 75 wt% and C is 25 to 99.
An interface layer containing 5 wt% and O of 0.001 to 30 wt%.

Here, the "neighborhood" in the above (i)
Is preferably a region whose distance from the crystalline particles is 100 nm or less.

The above "self-repairing" system is
Although not certain, it is considered that the following reactions (1) to (3) are occurring. (1) Part of the interface layer is oxidized, excess carbon is consumed, and SiO ₂ is formed in the interface layer. (2) SiO ₂ generated by oxidation and a part of the interface layer left without being oxidized or existing near the surface of the inorganic fiber,
Between S and Ti, Ti and / or Zr, C, and O, which is substantially amorphous or β-SiC crystalline, S
Excess carbon is generated by the reaction of iC + O ₂ → SiO ₂ + C. (3) Excess carbon generated by the reaction of the above (2), SiO ₂ generated by oxidation and / or a part of the interface layer left without oxidation and / or a part of the structure near the surface of the inorganic fiber Are mixed and interact with each other.

In addition to the above reaction (2), SiC + O ₂ →
SiO + CO or 2 / 3SiC + O ₂ → 2 / 3Si
The reaction of O ₂ + 2 / 3CO is conceivable, but the reaction of (2) above is likely to occur in an atmosphere with a high partial pressure of CO gas [“J. Mat. Sci., Vol. 22, p. 3148 (1987). . ”]. If the above SiC + O ₂ → SiO + CO or 2 / 3S
Even if the reaction of iC + O ₂ → 2 / 3SiO ₂ + 2 / 3CO occurs, CO gas is generated in each reaction. In a very limited and narrow area inside the ceramic composite material, the generated CO gas is less likely to diffuse to the outside and the partial pressure of the CO gas is high, resulting in the reaction (2) above being likely to occur. Become.

The amount of the above interface layer is preferably 0.05 to 20 vol% with respect to the entire ceramic composite material.

The ceramic composite material of the present invention comprises the above surface-treated inorganic fibers and the above ceramics,
It can be easily produced by the following methods (e) to (h). Method (e): A method of blending the above-mentioned inorganic fiber and the raw material powder of ceramics and performing heat treatment or high-temperature pressure treatment. Method (f): A method in which ceramics serving as a matrix are adhered to the surface of the above-mentioned inorganic fibers by the PVD method or the CVD method, and then the aggregate is subjected to heat treatment or high-temperature pressure treatment. Method (g): As a matrix by a chemical vapor phase impregnation method (chemical vapor phase infiltration method, chemical vapor phase dipping method, CVI method) inside the aggregate of the above-mentioned inorganic fiber woven fabric, sheet, non-woven fabric or cut product Method of depositing ceramics. Method (h); a precursor polymer of ceramics that serves as a matrix in an aggregate of the above-mentioned inorganic fiber woven fabric, sheet, non-woven fabric, or short cut product, that is, polycarbosilane, polyzirconocarbosilane, polytitanocarbosilane , Perhydropolysilazane, polysilazastyrene, polycarbosilazane, polysilazane, polyborazine, etc., and then in vacuum or in Ar gas, N ₂ gas, NH ₃ gas or Si (C _m H _{2m + 1} ) _n H _{4 -n} (n = 0-4, m = 1-
6) A method of heat treatment in various atmospheres such as gas.

The above methods (e) to (h) will be described in more detail. In the above method (e), when the inorganic fibers are short fibers, the mixture is a mixture of short fiber-shaped inorganic fibers and ceramic raw material powder, and the inorganic fibers are long fibers, woven fabric, nonwoven fabric, or sheet form. When it is a product, a layered product in which these fiber layers and ceramic raw material powder layers are alternately laminated, or a fiber bundle of long fibers having ceramic raw material powder adhered to the fiber surface is formed into a woven fabric, a non-woven fabric, or a sheet form. After forming a laminate of the processed product and shaping it into the desired shape,
Alternatively, a ceramic composite material can be obtained by heating the ceramic raw material powder at the same time as molding and sintering the raw material powder.

In the above method (f), ceramics to be a matrix are adhered to the surface of the inorganic fiber by a known CVD method or PVD method.

In the case of utilizing the CVD method, when the matrix ceramics is a carbide, at least one gas or vapor of a metal halide, hydride, or organometallic compound which constitutes the ceramics, and C _n H _{2n +. 2}
(N = 1 or more) gas and / or a mixture with H ₂ gas,
When the matrix ceramics is a nitride, a mixture of the above gas or vapor with NH ₃ gas and / or N ₂ gas and / or H ₂ gas is used. When the matrix ceramics is an oxide, NO ₂ gas and And / or O ₂ gas and / or H ₂ O vapor, when the matrix ceramics is a boride: a mixture of the above gas or vapor and boron halide and / or H ₂ gas, matrix ceramics If is a silicide:
The gas or _{vapor, Si (C m H 2m +} 1) n H
_4-n (n = 0 to 4, m = 1 to 6) and / or Si (C _{m
H 2m + 1) n Cl 4} -n (n = 0~4, such as a mixture of m = 1 to 6) and / or _{SiH n Cl 4-n (n} = 0~4) and / or H ₂ gas A raw material gas of the CVD method known per se can be used.

When the PVD method is used, a compound or mixture prepared so as to have a composition that is the same as or very close to the composition of the target ceramics is used as a target, or a plurality of targets of the compound or mixture is used. After being subjected to PVD treatment so as to have the same composition as the target ceramics by alternately using the above, the ceramics can be attached to the surface of the inorganic fibers by performing heat treatment if necessary.

In the above method (g), the inorganic fiber is
When it is a short fiber, it is an aggregate of short fiber-like inorganic fibers,
Machine fibers are long fibers, woven fabrics, non-woven fabrics, or sheets.
In some cases, the matrix layer should be
If Lamix is carbide, the desired ceramic
Halides, hydrides and organometals of the metals
At least one gas or vapor of a compound, and C
_nH_{2n + 2}(N = 1 or more) Gas and / or H_TwoMixing with gas
If the matrix ceramics are nitride,
NH_ThreeGas and / or N_TwoGas and / or H_TwoWith gas
Mixtures where the matrix ceramics are oxides
Is the above gas or vapor, NO_TwoGas and / or O
_TwoGas and / or H_TwoThe mixture with O vapor is
If the ceramic of the substrate is boride: The above gas or
Is steam, boron halide and / or H_TwoMixing with gas
If the matrix ceramics are silicides
Is Si (C_mH_{2m + 1})_nH_4-n(N = 0-4, m = 1-
6) and / or Si (C_mH _{2m + 1})_nCl_4-n(N = 0
4, m = 1 to 6) and / or SiH_nCl_4-n(N = 0
~ 4) and / or H_TwoKnown per se such as mixture with gas
Using the CVD source gas of
Therefore, the inorganic ceramic composite material of the present invention can be molded.
be able to. In the case of this CVI method, if necessary, the above
An aggregate of short fibrous inorganic fibers or a product of the above fibrous layers
By providing a temperature gradient and / or a source gas pressure gradient to the layered product
Alternatively, supply of raw material gas and exhaust of reaction product gas are alternated.
The CVI process may be performed by repeating the above.

In the above method (h), a solution prepared by dissolving the ceramic precursor polymer in an organic solvent which is a good solvent for the precursor polymer used, such as toluene, xylene, or tetrahydrofuran, is used as the inorganic fiber, or A composite material is prepared by impregnating the above-mentioned aggregate of short fibrous inorganic fibers or a laminate of the above-mentioned fiber layers, removing the solvent from the impregnated product, and then performing heat treatment. In this method, in order to obtain a composite material without internal voids,
It is preferable to repeat the series of operations of impregnation of the precursor polymer, removal of the solvent, and heat treatment a plurality of times. Further, in this method, mineralization and sintering of the precursor polymer proceed at the same time.

The heat treatment temperature in each of the above methods (e) to (h) is usually 800 to 2000 ° C. The heat treatment is performed in an inert atmosphere such as N ₂ gas, Ar, or vacuum, or a reducing atmosphere such as H ₂ gas or CO gas.

The ceramic composite material of the present invention is
It is useful as a material for various molded products in the space field.

[0065]

The present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these. In the following, “parts” and “%” represent “parts by weight” and “% by weight”, respectively, unless otherwise specified.

Reference Example 1 2.5 liters of anhydrous xylene and 400 g of sodium were placed in a 5 liter three-necked flask and heated to the boiling point of xylene under N ₂ gas flow, and then 1 liter of dimethyldichlorosilane was added for 1 hour. Dropped. After dropping, 1
The mixture was heated under reflux for 0 hour to form a precipitate. This precipitate was filtered, and the precipitate was first washed with methanol and then with water to obtain 410 g of white powdery polydimethylsilane. 250 g of the obtained polydimethylsilane had an internal volume of 1
It was put in a liter induction rotary autoclave, degassed with a vacuum pump, and then filled with 1 atm of Ar gas. Then, with stirring, the temperature inside the container was heated to 470 ° C., and the reaction was carried out at 470 ° C. for 15 hours. The pressure inside the container after the reaction was about 105 kg / cm ² . Then, the mixture was cooled to room temperature, the reaction product was taken out as an n-hexane solution, filtered, and then distilled under reduced pressure to 2
The low molecular weight product having a boiling point of up to 80 ° C./1 mmHg was removed, and 140 g of a light brown solid state number average molecular weight of 1
850 polycarbosilane were obtained.

Reference Example 2 750 g of diphenyldichlorosilane and 124 g of boric acid
In n-butyl ether under N ₂ gas flow of 100-1
The mixture was heated at 20 ° C., and the produced white resinous material was further heat treated at 400 ° C. for 1 hour in vacuum to obtain 515 g of polyborodiphenylsiloxane. This polyborodiphenylsiloxane 8.2 g was mixed with 250 g of the polydimethylsilane obtained in Reference Example 1 and heated to 350 ° C. under a N ₂ gas stream in a quartz tube equipped with a reflux tube to give 350
The mixture was kept at 6 ° C. for 6 hours while stirring to obtain 138 g of polycarbosilane partially containing a siloxane bond. Of 40 g of this polycarbosilane and 7.3 g of titanium tetrabutoxide dissolved in 0.3 liter of xylene, 1 in N ₂ gas was used.
Refluxed at 20 ° C. for 30 minutes with stirring. Then, xylene was evaporated and further heated at 300 ° C. for 1 hour in N ₂ gas to obtain solid polytitanocarbosilane at room temperature.

Reference Example 3 The polytitanocarbosilane obtained in Reference Example 2 was melt-spun at 210 ° C. in a N ₂ gas stream to obtain a fiber made of an inorganic material. Then, the obtained fiber is heated from room temperature to 190 ° C. at a heating rate of 15 ° C./hour in air without tension,
The infusible fiber was obtained by holding at 190 ° C. for 4 hours. The infusible fiber thus obtained was heated to 1000 ° C. at a temperature rising rate of 100 ° C./hour under N ₂ gas flow without tension, held at 1000 ° C. for 1 hour, and then held in air at 1000 ° C. for 15 minutes. Then
Furthermore, at a heating rate of 100 ° C./hour under a CO gas flow, 1
The surface treatment [the above method (d)] was performed by raising the temperature to 330 ° C., holding at 1330 ° C. for 3 hours and baking. By this firing, an inorganic fiber having a fiber diameter of about 11 μm and having a surface layer formed on the surface of the fiber body was obtained. The ratio of the constituent elements of the whole surface-treated inorganic fiber is as follows: silicon 52%, carbon 33%, titanium 4%, oxygen 11%.
Met.

The obtained inorganic fiber was subjected to Auger electron spectroscopic analysis near its surface (near the surface including the surface layer). The result is shown in FIG. In FIG. 1, the concentration distribution of constituent elements in the thickness direction from the surface layer to the surface of the inorganic fiber is shown in mol%. As is clear from the results shown in FIG. 1, in this inorganic fiber, a surface layer having a thickness of about 70 nm is formed on the surface of the fiber body, and the surface layer contains silicon in an amount of 48% → 56% → 55%. , 12% carbon
→ 9% → 22%, oxygen continuously changes from 36% → 26% → 16%, and has an outermost layer (thickness of about 10 nm) containing 4 to 9% of titanium, and has a depth from the outermost surface. Is 10 nm to 7
In the range of 0 nm, the silicon content increases from 55% to 33% to 52%,
22% → 53% → 33% carbon, 16% → 12 oxygen
% → 11%, and the second layer (thickness: about 10 to 60 nm) had a structure containing 2 to 7% of titanium. In addition, the structure of the fiber main body was that the average crystallite size of β-SiC was 2 nm or less in X-ray diffraction and was amorphous in electron beam diffraction. And is amorphous consisting of carbon and oxygen,
And each elemental composition is about 52% for silicon and about 4 for titanium.
%, Carbon was about 33%, oxygen was about 11%, and the elemental compositions were almost constant up to the center of the fiber, and the structure of the fiber body and the structure of the surface layer were clearly different.

Reference Example 4 The polytitanocarbosilane obtained in Reference Example 2 was melt-spun at 210 ° C. in a N ₂ gas stream to obtain a fiber made of an inorganic material. Then, the obtained fiber was irradiated with an electron beam up to 15 MGy in a temperature range from room temperature to 120 ° C. in a He gas stream, and then heated to 425 ° C. in a Ar gas stream at a heating rate of 200 ° C./hour. The infusible fiber was obtained by holding at 425 ° C. for 2.5 hours. The infusible fiber thus obtained was subjected to 100% tension-free heating under a N ₂ gas stream at a temperature rising rate of 300 ° C./hour.
After heating to 0 ° C. and heat treatment, and holding at 1000 ° C. for 30 minutes, the temperature was raised to 1400 ° C. at a heating rate of 100 ° C./hour without tension in a CO gas stream, and further 1400 ° C.
Surface treatment [the above method (C)] was carried out by holding at 1 hour and baking. As a result, an inorganic fiber having a fiber diameter of about 10 μm and having a surface layer formed on the surface of the fiber body was obtained. The ratio of constituent elements of the obtained surface-treated inorganic fiber was 52% for silicon, 38% for carbon, 3% for titanium, and 7% for oxygen.

The surface of the obtained inorganic fiber (the surface including the surface layer) was analyzed by Auger electron spectroscopy. The result is shown in FIG. In FIG. 2, the concentration distribution of constituent elements in the thickness direction from the surface layer to the surface of the inorganic fiber is shown in mol%. As is clear from the results shown in FIG. 2, this surface-treated inorganic fiber has a thickness of about 120 nm on the surface of the fiber body and 4% to 5% silicon.
It had a surface layer containing 2%, 89% → 38% carbon, 4% → 7% oxygen, and about 3% titanium. In the structure of the fiber body, the average crystallite size of β-SiC is 5 nm or less in terms of X-ray diffraction, and β of 5 to 10 nm is observed by a transmission electron microscope.
Since -SiC crystals and TiC crystals of 5 to 20 nm were confirmed, amorphous consisting essentially of silicon, titanium, carbon and oxygen, and β-S having a size of 5 to 10 nm.
It is a mixed system of iC crystals and TiC crystals having a size of 5 to 50 nm, and the average composition of each element is about 52 for silicon.
%, Titanium about 3%, carbon about 38%, oxygen about 7%
The average composition of each element in the depth direction of the fiber was almost constant up to the center, and the structure of the fiber body and the structure of the surface layer were clearly different.

Example 1 In a mixed solution of 100 parts of polycarbosilane obtained in Reference Example 1 and 100 parts of hexane, a three-dimensional woven fabric prepared from the inorganic fibers obtained in Reference Example 3 [fiber density X-axis direction: Y Axial direction: Z-axis direction (weight ratio) = 1: 1: 0.1] is immersed and degassed under a reduced pressure of 500 Torr, and then the above three-dimensional fabric is mixed with the above three-dimensional fabric in an argon gas atmosphere of 4 atm. The solution was impregnated. The three-dimensional fabric after impregnation was heated to 80 ° C. under an argon gas stream to evaporate and remove hexane. Next, the impregnated product from which hexane had been removed was heated in an electric furnace to 1350 ° C. at a heating rate of 50 ° C./hour under a nitrogen gas stream, held at 1350 ° C. for 1 hour, and then heated to 1000 ° C. for 1 hour.
The temperature was decreased at a temperature decrease rate of 00 ° C./hour, and then the mixture was allowed to cool to room temperature and calcined. By repeating this impregnation and firing 10 times, the ceramic composite material of the present invention was obtained. FIG. 3 shows a transmission electron micrograph of the vicinity of the interface between the fiber portion and the matrix portion in the obtained ceramics composite material, that is, the interface layer and its periphery.

In FIG. 3, the region sandwiched by the arrows A is the interface layer. Then, from the analysis result by the energy dispersive X-ray spectroscopic analyzer and the electron diffraction result, 1 in the photograph was obtained.
It was revealed that is a β-SiC crystal particle, 2 is a TiC crystal particle, 3 and 4 are amorphous composed of Si, Ti, C, and O, and 5 is a carbon crystal particle. As is clear from the results shown in FIG. 3, an interface layer having a thickness of about 50 nm was formed between the fiber portion and the matrix portion in the obtained composite material, and the energy dispersive X-ray spectroscopic analysis apparatus was used. From the analysis results and the electron beam diffraction results, this interface layer was composed of Si, Ti, C, and O.
It was found to be composed of β-SiC crystal particles, TiC crystal particles and carbon crystal particles having a size of m or less.

The bending strength of the obtained composite material is 550MP.
and the bending strength after heat treatment for 110 hours at 1250 ° C. in air was 500 MPa. Moreover, as a result of observing the vicinity of the interface between the fiber and matrix of the composite material after the heat treatment with a transmission electron microscope equipped with an energy dispersive X-ray spectroscopic analyzer, the interface layer that was initially formed was oxidized and An oxide layer of silicon oxide having a thickness of 50 to 70 nm was formed between them, but an amorphous layer composed of Si, Ti, C, and O having a thickness of 10 to 20 nm was formed between the oxide layer and the fiber. It was found that a new interface layer composed of TiC crystal particles and carbon crystal particles having a size of 10 nm or less was formed.

Example 2 A plain woven fabric [fiber density X-axis direction: Y-axis direction (weight ratio) = 1: 1] prepared from the inorganic fibers obtained in Reference Example 4 was used as 8
The fiber laminate obtained by stitching at 0.5 cm intervals after layer lamination was immersed in a mixed solution of 100 parts of polytitanocarbosilane obtained in Reference Example 2 and 100 parts of xylene, and 4
After degassing under a reduced pressure of 00 Torr, the above fiber laminate was impregnated with the same mixed solution as used in Example 1 in the same manner as in Example 1 in an Ar gas atmosphere of 5 atm. Then, the laminate after impregnation (hereinafter referred to as "impregnation product") is
It was heated to 150 ° C. under a stream of r gas to remove xylene by evaporation.

Next, the impregnated product from which xylene was removed was heated in an electric furnace under a N ₂ gas stream at a temperature rising rate of 30 ° C./hour for 13 times.
After heating to 50 ° C and holding at 1350 ° C for 1 hour,
The temperature was lowered to 000 ° C. at a temperature lowering rate of 100 ° C./hour, then allowed to cool to room temperature, and the impregnated material was calcined. By repeating this impregnation and firing 10 times, the ceramic composite material of the present invention was obtained. Near the interface between the fiber portion and the matrix portion in the obtained ceramic composite material, that is,
The interface layer and its periphery were observed with a transmission electron microscope equipped with an energy dispersive X-ray spectroscopic analyzer. A transmission electron micrograph at that time is shown in FIG.

In FIG. 4, the region sandwiched by the arrows A is the interface layer. Analysis results and electron diffraction results by the energy dispersive X-ray spectrophotometer, 1 in the photograph is β-SiC
Crystal particles, 2 TiC crystal particles, 3 and 4 Si
It was found that the amorphous material 5 composed of Ti, C and O was a crystal particle of carbon. As is clear from the results shown in FIG. 4, an interface layer having a thickness of 20 to 60 nm is formed between the fiber portion and the matrix portion in the obtained composite material, and the energy dispersive X-ray spectroscopic analyzer According to the analysis result and the electron beam diffraction result, the interface layer is composed of Si, T
It was found to be composed of an amorphous material composed of i, C, and O, β-SiC crystal particles having a size of 20 nm or less, TiC crystal particles, and carbon crystal particles.

The bending strength of the obtained composite material is 680 MP.
and the bending strength after heat treatment at 1250 ° C. for 100 hours in air was 675 MPa. Further, FIG. 5 shows a transmission electron microscope photograph of the periphery of the interface layer in the ceramic composite material after the heat treatment.

In FIG. 5, the region sandwiched by the arrow A is an oxide layer, and the region sandwiched by the arrow B is a newly formed interface layer. Analysis results and electron beam diffraction results by the energy dispersive X-ray spectroscopic analyzer. In FIG. 5, 1 is inorganic fiber, 2 is β-SiC crystal particles, 3 and 4 are amorphous composed of Si and O, and 5 is Matrix, 6 is crystal particles of TiC, 7 is amorphous composed of Si, Ti, C and O, 8
Was an aggregate of carbon. Further, in FIG. 6, 1 is β-SiC
Crystal particles, 2 TiC crystal particles, 3 and 4 Si
Amorphous, consisting of Ti, C, and O, and 5 were aggregates of carbon. From FIGS. 5 and 6 and the analysis results by the energy dispersive X-ray spectroscopic analyzer, the interface layer that was initially formed was oxidized, and the oxidation of silicon oxide having a thickness of 45 to 70 nm was performed between the fiber portion and the matrix portion. Although a layer was formed, 30 nm of Si was formed between the oxide layer and the fiber,
Amorphous consisting of Ti, C, and O, T of 30 to 50 nm
It was found that a new interface layer composed of iC crystal particles, β-SiC crystal particles of 10 nm or less, and carbon crystal particles was formed.

Comparative Example 1 Inorganic fibers were prepared by coating commercially available "Tyranno fiber TM-S1" [trade name, manufactured by Ube Industries, Ltd.] with ethane gas as a raw material and carbon with a thickness of about 200 nm by a CVD method. . A plain woven fabric prepared from this inorganic fiber in the same manner as in Example 2 [fiber density X-axis direction: Y-axis direction (weight ratio) =
1: 1] 8 layers and then stitched at intervals of 0.5 cm is immersed in a mixed solution of 100 parts of polytitanocarbosilane obtained in Reference Example 2 and 100 parts of xylene, and the pressure is reduced to 400 Torr. After degassing under the above conditions, the above-mentioned laminate was impregnated with the above mixed solution in an Ar gas atmosphere at 5 atm. Laminate after impregnation (hereinafter referred to as "impregnation")
Was heated to 150 ° C. under Ar gas flow to remove xylene by evaporation.

Next, the impregnated product from which xylene had been removed was placed in an electric furnace under a N ₂ gas stream at a temperature rising rate of 30 ° C./hour for 13 times.
After heating to 50 ° C and holding at 1350 ° C for 1 hour,
The temperature was lowered to 000 ° C. at a temperature lowering rate of 100 ° C./hour, then allowed to cool to room temperature, and the impregnated material was calcined. This impregnation and firing were repeated 10 times to obtain a ceramic composite material. As a result of observing the vicinity of the interface between the fiber portion and the matrix portion of the obtained ceramic composite material with a transmission electron microscope equipped with an energy dispersive X-ray spectroscopic analysis device, it was found that between the fibers and matrix in the obtained composite material An interface layer having a thickness of about 200 nm was formed, and the interface layer was composed of carbon. The bending strength of the obtained composite material is 500 MPa, and it is 100 at 100 ° C. in air.
The bending strength after the heat treatment for 25 hours was 25 MPa.

Regarding the obtained ceramic composite material,
As a result of observing the state of the interface layer after the heat treatment with a transmission electron microscope with an energy dispersive X-ray spectroscopic analyzer,
The initially formed interface layer of carbon disappeared, and an oxide layer of silicon oxide having a thickness of about 80 nm was formed between the fiber and the matrix. Also, inside this oxide layer,
Alternatively, a novel interface layer as observed in Examples 1 and 2 was not formed between the oxidized layer and the fiber or between the oxidized layer and the matrix.

[0083]

INDUSTRIAL APPLICABILITY The ceramic composite material of the present invention has little deterioration in mechanical properties when it is actually used at high temperature even in an environment where oxygen and water vapor exist, such as in the atmosphere.

[Brief description of drawings]

FIG. 1 is a chart showing Auger electron spectroscopic analysis results in the depth direction from the surface (surface layer) of the surface-treated inorganic fiber obtained in Reference Example 3.

FIG. 2 is a chart showing Auger electron spectroscopic analysis results from the surface (surface layer) of the surface-treated inorganic fiber obtained in Reference Example 4 in the depth direction.

FIG. 3 is a transmission electron micrograph (a photograph submitted in place of a drawing and showing a structure of a ceramic material) around the interface layer of the ceramic composite material obtained in Example 1. .

FIG. 4 is a transmission electron micrograph of the ceramic composite material obtained in Example 2 (a photograph submitted in place of the drawing and showing the structure of the ceramic material).

FIG. 5 is a transmission electron microscope photograph of the periphery of the interface layer after heat-treating the ceramic composite material obtained in Example 2 (a photograph submitted in place of the drawing, which shows the structure of the ceramic material. (Photo).

FIG. 6 is a transmission electron microscope photograph of the periphery of the interface layer after heat treatment of the ceramic composite material obtained in Example 2 (a photograph submitted in place of the drawing, which shows the structure of the ceramic material). (Photograph), which has a higher magnification than FIG.

Claims (7)

[Claims] 1. A fiber composed of a plurality of inorganic fibers having a fiber body and a surface layer located on the surface of the fiber body and having a structure different from that of the fiber body, and ceramics. Part, a matrix part made of the above-mentioned ceramics and located around the fiber part,
And a ceramic composite material comprising an interface layer having a self-repairing property, which is formed between the fiber portion and the matrix portion by reacting the surface layer with the ceramics. 2. The interface layer has a thickness of 3 nm or more, and (g) is substantially Si, Ti and / or Zr,
Amorphous consisting of C and O, (h) the above amorphous and 10
Β-SiC of 00 nm or less, TiC and / or ZrC
And a crystalline aggregate of C or (i) the above crystalline: and an amorphous mixed system composed of SiOx and TiOx and / or ZrOx (0 <x ≦ 2) existing in the vicinity thereof. And the average elemental composition of Si is 0.5
˜50 wt%, Ti and / or Zr is 0.05-20 w
t%, C 30 to 99.0 wt%, O 0.001 to 4
It is 0 wt%, The ceramic composite material of Claim 1 characterized by the above-mentioned. 3. The interface layer has a thickness of 3 nm or more, (j) an amorphous material consisting essentially of Si, C, and O, (k) the amorphous material, and 1000 nm or less. β-S
iC crystalline, (l) the amorphous and crystalline, or (m) the amorphous and / or crystalline, and a mixed system of carbon aggregates, and the average composition thereof is The ceramic composite material according to claim 1, wherein Si is 0.1 to 75 wt%, C is 25 to 99.5 wt%, and O is 0.001 to 30 wt%. 4. The ceramic composite material according to claim 1, wherein the structure of the fiber body is the following structure, and the structure of the surface layer is the following structure (A) or (B). Structure; (a) Substantially Si, Ti and / or Zr, C and O
And (b) the above amorphous and 1000n
A crystalline aggregate of β-SiC of m or less and TiC and / or ZrC, or (c) SiOx existing in the above crystalline and its vicinity, TiOx and / or ZrOx.
(0 <x ≦ 2), which is an amorphous mixed system and has an average elemental composition of 30 to 80 wt% Si and Ti.
And / or Zr is 0.05 to 8 wt% and C is 15 to 69.
A structure in which wt% and O are 0.01 to 20.0 wt%. Structure (A): Si changes continuously or stepwise from 0.5 to 20 wt% to the average composition value of the inorganic fiber, and C is 80
.About.99.5 wt% to the average composition value of the inorganic fiber continuously or stepwise, O continuously changes from 0 to 19.5 wt% to the average composition value of the inorganic fiber, and Ti and / Or a structure containing 0 to 10 wt% of Zr. Structure (B); Si from 20 to 80 wt% to 0 to 60 wt%
Changes continuously or stepwise until C is 0 to 50 wt
% From 40% to 40 to 100 wt% continuously or stepwise, O changes from 2 to 80 wt% from 0 to 45 wt% continuously or stepwise, and contains Ti and / or Zr from 0 to 10 wt% It has a structure as the outermost layer, and Si changes continuously or stepwise from 0 to 60 wt% to the average composition value of the inorganic fiber, and C is 40 to 10
It changes continuously or stepwise from 0 wt% to the average composition value of the inorganic fiber, and O changes continuously or stepwise from 0 to 45 wt% to the average composition value of the inorganic fiber,
A structure having a structure containing 0 to 10 wt% of Ti and / or Zr as a second layer. 5. The ceramic composite material according to claim 1, wherein the structure of the fiber main body is the following structure, and the structure of the surface layer is the following structure (C) or (D). Structure; (d) Amorphous consisting essentially of Si, C, and O,
(E) a crystalline aggregate of β-SiC of 1000 nm or less, amorphous SiO ₂ and / or substantially Si, and C,
O is an aggregate with an amorphous material, or (f) is a mixed system of the above-mentioned amorphous material and / or the above aggregate, and an aggregate of carbon, and the average elemental composition thereof is that Si is 30 to 30%. 80w
t%, C 10 to 65 wt%, O 0.01 to 25 wt
%, H is 2 wt% or less. Structure (C); Si continuously or stepwise changes from 0.5 to 20 wt% to the average composition value of the inorganic fiber, and C is 75
A structure that continuously or stepwise changes from ˜99 wt% to the average composition value of the inorganic fiber, and O changes continuously or stepwise from 0 to 24.5 wt% to the average composition value of the inorganic fiber. Structure (D); Si from 20 to 80 wt% to 0 to 55 wt%
Changes continuously or stepwise until C is 0 to 55 wt
% To 45 to 100 wt% continuously or stepwise, and O as an outermost layer having a structure in which O continuously or stepwise changes from 2 to 80 wt% to 0 to 24.5 wt%, and Si is 0 .About.55 wt% to the average composition value of the inorganic fiber continuously or stepwise, and C is 45 to 1
The second layer has a structure in which it changes continuously or stepwise from 00 wt% to the average composition value of the inorganic fiber, and O changes continuously or stepwise from 0 to 24.5 wt% to the average composition value of the inorganic fiber. Construction. 6. The ceramic composite material according to claim 1, wherein the surface layer has a thickness of 10 nm or more. 7. The ceramic is a carbide, a nitride,
The ceramic composite material according to claim 1, which is at least one selected from the group consisting of borides, silicides and oxides.