JPH05148045A - Composite material of inorganic fiber reinforced ceramics - Google Patents

Abstract

PURPOSE:To improve strength, toughness and heat resistance of composite material with inorganic fiber material by using inorganic fibers consisting of an inner layer part and a surface layer part composed of silicon, carbon, titanium, etc., as a reinforcing material and a ceramics as a matrix. CONSTITUTION:The objective composite material is composed of inorganic fibers as a reinforcing material and a ceramics as a matrix. The inorganic fibers consist of an inner layer part comprising 40-60wt.% silicon, 20-40wt.% carbon, 0.5-10wt.% titanium or zirconium and 10-30wt.% oxygen and a surface layer comprising 0-40wt.% silicon, 50-100wt.% carbon, 0-8wt.% titanium or zirconium and 0-25wt.% oxygen. The surface layer part formed in a zone of >=500nm from the surface has an inclined composition distribution having a continuously increasing carbon ratio toward the surface of fibers.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an inorganic fiber reinforced ceramic composite material having high strength, toughness and heat resistance.

[0002]

BACKGROUND OF THE INVENTION Ceramic Bulletin Vol. 67 No. 11 (1988) The 1779-1782 pages, _LiO-Al 2 O reinforced with silicon carbide fibers
About 90 kg / m of ₃ -SiO ₂ based crystallized glass composite material
Maximum bending strength of m ² at room temperature and 15 MPa · m ^1/2
It has been described that it has a fracture toughness value of. Journal of the Ceramic Society of Japan Vol. 99, No. 1, 1991
On pages 89-93, a composite of mullite and 40% by volume silicon nitride whiskers has a flexural strength of about 35 kg / mm ² to about 65 kg compared to mullite alone.
/ Mm ² and the critical stress intensity factor (K _IC ) as a guide for the fracture toughness value is about 2 MPa · m ^1/2 to about 4 MP
It is disclosed that it is improved to a · m ^1/2 . These composite materials have the main characteristics required for the ceramic member for gas turbine as described on page 32 of “Ceramics Reinforced Composite Ceramics” issued by Industrial Technology Center Co., Ltd., such as heat resistant temperature of 1250 to 1500 ° C.
It does not satisfy the minimum guaranteed strength of 40 to 60 kg / mm ² or more and the critical stress coefficient of 6.7 to 15 MPa · m ^1/2 . It is required to improve the performance of various heat engines such as automobile engines, and accordingly, development of a ceramic material having excellent heat resistance and excellent strength and fracture toughness values from room temperature to high temperature is strongly desired. ing.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an inorganic fiber reinforced ceramic composite material which satisfies the above demands. According to the present invention, in an inorganic fiber-reinforced ceramic composite material using inorganic fibers as a reinforcing material and ceramics as a matrix, the inorganic fibers are 40 to 60% by weight of silicon, 20 to 40% by weight of carbon, and 0.5 or 0.5 of titanium or zirconium. -10 wt% and oxygen 10-30
The inner layer portion is composed of 0 to 40% by weight, the surface layer portion is composed of 0 to 40% by weight of silicon, 50 to 100% by weight of carbon, 0 to 8% by weight of titanium or zirconium, and 0 to 25% by weight of oxygen. Has a gradient composition distribution that continuously increases toward the fiber surface in the surface layer portion formed in a region of 500 nm or less from the surface, and the inorganic fiber is (1) silicon, carbon, titanium or zirconium, And an amorphous substance consisting of oxygen, (2) β-SiC, MC, C, a solid solution of β-SiC and MC, and at least one selected from the group consisting of MC _1-x and having a particle size of 50 nm or less. Of the crystalline fine particles of (3) and amorphous SiO ₂ and MO ₂ or (3) a mixture of the amorphous substance of (1) above and the aggregate of (2) above (wherein M Is titanium or zirconium Shows,
x is a number greater than 0 and less than 1. An inorganic fiber reinforced ceramic composite material is provided.

The inorganic fiber in the present invention is composed of the inner layer portion and the surface layer portion having the above composition ratio, and the fiber diameter is usually 5 to 2
It is 0 μm. The surface layer portion of the inorganic fiber is formed within the region of 500 nm or less from the fiber surface toward the fiber axis center and on the fiber surface side. When the surface layer portion is formed in a region deeper than the above range, the proportion of the inner layer portion is relatively reduced, and as a result, the mechanical properties of the inorganic fiber are deteriorated. In the surface layer portion of the inorganic fiber, for example, as shown in FIG. 1, the proportion of carbon increases continuously toward the fiber surface. FIG. 1 shows the relationship between the depth (nm) from the fiber surface and the proportion (% by weight) of the constituent elements of the inorganic long fiber obtained in Reference Example 1 described later, and the proportion of carbon is about from the fiber surface. It is understood that there is a sharp increase from the point of 20 nm toward the fiber surface. On the other hand, with respect to the inorganic fiber obtained by spinning, infusibilizing, and then firing at a constant temperature, polytitanocarbosilane prepared according to the method described in JP-B-62-60414, which will be described later, the depth and composition from the fiber surface. According to FIG. 2 showing the relationship with the ratio of elements, it is understood that the ratio of elements constituting the fiber is substantially constant in the depth direction of the fiber.

Since the inorganic fiber in the present invention has a thin layer rich in carbon near the surface of the fiber, the composite material of the inorganic fiber and the ceramic includes an interface layer made of carbon and a carbide between the fiber and the matrix. Or an interface layer made of carbon and carbide is formed. The presence of this interfacial layer suppresses the extreme reaction between the fiber and the matrix and the decomposition of the fiber, and maintains the interfacial bond state between the fiber and the matrix in an optimum state. As a result,
The inorganic fiber-reinforced ceramic composite material of the present invention exhibits excellent mechanical properties and high toughness from room temperature to high temperature. There is no special limitation on the usage form of the inorganic fiber,
It may be a continuous fiber or a chopped short fiber obtained by cutting a continuous fiber, or may be a plain weave, satin weave, multiaxial weave, three-dimensional weave, or a non-woven fabric knitted from a continuous fiber. It may be a sheet-like material that is aligned.

The inorganic fiber in the present invention can be prepared, for example, according to the production method disclosed in the specification of Japanese Patent Application No. 3-179070 previously proposed by the present applicant. Polytitanocarbosilane or polyzirconocarbosilane (hereinafter, both are collectively referred to as “precursor polymer”) used for producing inorganic fibers is described in, for example, JP-B-61-4.
No. 9335, No. 62-60414, No. 63-
It can be prepared according to the methods described in 37139 and 63-49691. The descriptions of these publications are referred to as part of the present specification. The precursor polymer is (1) by reacting polycarbosilane with polytitanosiloxane or polyzirconosiloxane to give a silicon atom of polycarbosilane and a silicon atom of the siloxane polymer, or a titanium atom or a zirconium atom. By reacting polycarbosilane with an alkoxide of titanium or zirconium by reacting polycarbosilane with an oxygen atom. Included are polymers attached through.

The above precursor polymer is spun by a conventional method and then infusibilized. As a method for making the spun fiber infusible, a method known per se, for example, a method of heating the spun fiber at a temperature in the range of 50 to 400 ° C. in an oxidizing gas atmosphere, or irradiating the spun fiber with γ-rays or electron beams The method can be adopted. The spinning and infusibilization of the precursor polymer are described in Japanese Patent Publication No. Sho 60-1405 related to the applicant's application.
No. 60-20485, and the description of these publications is referred to as part of the present specification. The infusibilized fiber is then continuously fed to a continuous firing furnace and fired. In order to prepare the inorganic fiber in the present invention, it is necessary to increase the temperature in the firing furnace in the traveling direction of the fiber. This treatment can be easily performed by, for example, increasing the temperature of the firing furnace stepwise or continuously in the direction of fiber movement. The temperature gradient formed in the firing furnace varies depending on the amount of the infusible fiber to be treated, the length of the firing furnace, and the like, and cannot be uniformly defined, but generally 50 to 1000 ° C / m.
(Furnace length) range.

The maximum firing temperature is in the range of 800 to 2000 ° C, preferably 1200 to 1600 ° C. As described above, the temperature in the firing furnace is increased in the advancing direction of the fibers, but the maximum firing temperature means the highest temperature reached in the firing furnace. If the final firing temperature is lower than 800 ° C, the inorganic fiber having high mechanical strength cannot be obtained, and the final firing temperature is 20%.
If the temperature is higher than 00 ° C., rapid crystallization of silicon carbide and evaporation of silicon carbide occur, so that the strength of the obtained inorganic fiber is significantly reduced. The inlet temperature of the firing furnace is room temperature to 800
The temperature is preferably in the range of 50 ° C., particularly 50 to 200 ° C. If the inlet temperature of the firing furnace is excessively high, it becomes impossible to form a sufficient temperature gradient in the firing furnace, and it becomes difficult to obtain the desired inorganic fiber having a graded surface composition. Firing of the infusible fiber is carried out under tension in an atmosphere of an inert gas such as nitrogen or argon, or in vacuum. There is no particular limitation on the tension applied to the fiber, but generally 10 to
It is 300 g / mm ² . According to this manufacturing method, it is possible to efficiently obtain the inorganic fiber including the inner layer portion and the surface layer portion described above. Without being bound by any theory for the reason, an inorganic fiber having almost the same composition as that of the inner layer is first formed, and then silicon, titanium or zirconium, and at least a part of oxygen are isolated from the surface of the fiber. Alternatively, it is presumed that it escapes as a compound, and as a result, a surface layer portion having a high proportion of carbon atoms is formed.

The matrix ceramics in the present invention include crystalline or amorphous oxide ceramics, crystalline or amorphous non-oxide ceramics, glass, crystallized glass, mixtures thereof, and these ceramics. A ceramic composite material having a particle dispersion strengthened can be exemplified. Specific examples of oxide ceramics include aluminum, magnesium, silicon, yttrium, indium, uranium, calcium, scandium,
Tantalum, niobium, neodymium, lanthanum, ruthenium,
Rhodium, beryllium, titanium, tin, strontium,
Examples thereof include oxides of elements such as barium, zinc, zirconium and iron, and composite oxides of these metals. Examples of non-oxide ceramics include carbides, nitrides and borides. Specific examples of the carbide include carbides of elements such as silicon, titanium, zirconium, aluminum, uranium, tungsten, tantalum, hafnium, boron, iron and manganese, and composite carbides of these elements. Specific examples of the nitride include nitrides of elements such as silicon, boron, aluminum, magnesium and molybdenum, composite nitrides of these elements, and sialon. Specific examples of borides include borides of elements such as titanium, yttrium, and lanthanum, CeCo.
_{3 B 2, CeCo 4 B 4} , boride platinum group lanthanoid and the like, such as ErRh ₄ B _4.

Specific examples of the glass include amorphous glasses such as silicate glass, phosphate glass and borate glass. As a specific example of the crystallized glass, LiO ₂ —Al ₂ O whose main crystal phase is β-spodumene
₃ -MgO-SiO ₂ based glass and _LiO 2 _-Al 2 O
_{3 -MgO-SiO 2 -Nb 2 O} 5 based glass, _MgO-Al 2 main crystal phase is cordierite O 3 -SiO ₂
System glass, Ba whose main crystal phase is barium osmilite
_{O-MgO-Al 2 O 3} -SiO 2 based glass, BaO-Al ₂ main crystalline phase is mullite or hexacelsian
O ₃ -SiO ₂ based glass, a main crystal phase include _CaO-Al 2 O 3 -SiO ₂ based glass is anorthite. The crystal phase of these crystallized glasses may contain cristobalite. Examples of the ceramics in the present invention include solid solutions of the above various ceramics. Specific examples of the ceramic composite material in which ceramic particles are dispersed and strengthened include silicon nitride, silicon carbide,
0.1-60% by volume of spherical particles, polyhedral particles, plate-like particles and rod-like particles of an inorganic substance selected from zirconium oxide, magnesium oxide, kalim titanate, magnesium borate, zinc oxide, titanium boride and mullite. Examples include dispersed ceramics. The particle system of spherical particles and polyhedral particles is generally 0.1 μm to 1 mm, and the aspect ratio of plate-like particles and rod-like particles is generally 1.5 to 1000.

The inorganic fiber-reinforced ceramic composite material of the present invention can be prepared by blending inorganic fibers and ceramic raw material powder according to a method known per se and sintering. When the inorganic fiber is a chopped material, it can be a mixture of chopped inorganic fiber and ceramic raw material powder, and when the inorganic fiber is a long fiber, woven fabric, non-woven fabric or sheet-shaped product, these It is possible to obtain a laminate in which layers and ceramic raw material powder layers are alternately laminated. Next, the above-mentioned mixture or laminate is molded into a desired shape, or is heated and sintered at the same time as molding, whereby the inorganic fiber-reinforced ceramic composite material of the present invention can be obtained. As a method for molding the mixture or laminate, a die pressing method, a rubber pressing method,
A known method such as an extrusion method or a sheet method can be adopted. As the binder at the time of molding, known organic polymers such as polyvinyl alcohol, aluminum alkoxide polymers, polycarbosilane, and polymetallocarbosilane can also be used. There is also no particular limitation on the sintering method, and a method known per se such as a method of sintering a molded product under normal pressure or a reduced pressure, a hot pressing method or a hot isostatic pressing method of simultaneously performing molding and sintering. Can be adopted. Heating and sintering temperature is usually 400-2
It is 200 ° C. If the heating and sintering temperature is excessively low, sintering of the matrix will not proceed sufficiently, and if the temperature is excessively high, the matrix or the inorganic fibers will be decomposed.

[0012]

The present invention will be described below with reference to examples. Unless otherwise specified below, "part" and "%" are
"Parts by weight" and "% by weight" are shown, respectively. Reference Example 1 To 100 parts of polydimethylsilane synthesized by dechlorinating and condensing dimethyldichlorosilane with sodium metal, 3 parts of polyborosiloxane was added, and heat-condensed at 350 ° C. in nitrogen to obtain a compound of the formula —Si— A polycarbosilane having a main chain skeleton mainly composed of a carbosilane unit represented by CH ₂ — and having a hydrogen atom and a methyl group in the silicon atom of this carbosilane unit was prepared. This polycarbosilane 1
Titanium tetrabutoxide (20 parts) was added to 00 parts, and a cross-linking reaction was performed at 340 ° C. in nitrogen to obtain a polytitanocarbo composed of 100 parts of the above carbosilane unit and 10 parts of the titanoxane unit represented by the formula —Ti—O—. Obtained silane. Melt spinning this polytitanocarbosilane,
Then, it was heated in air at 190 ° C. to obtain an infusible fiber having a diameter of 15 μm.

A continuous firing furnace having a length of 8 m is provided with four temperature zones, and a first zone, a second zone, a third zone and a fourth zone.
The temperature of the zone is set to 300 to 500 ° C. and 500, respectively.
~ 800 ° C, 800-1300 ° C and 1300-160
It was set to 0 ° C. In the firing furnace that formed this temperature gradient,
The infusible fiber was continuously supplied from the first zone at a rate of 3 m / min and fired in an argon gas atmosphere. The obtained inorganic fiber was continuously taken out from the outlet of the fourth zone. The diameter of the obtained inorganic fiber was 11 μm. The composition distribution in the fiber axis direction from the surface of this inorganic fiber was measured by a scanning Auger electron spectrometer JAMP-30 manufactured by JEOL Ltd.
Was analyzed. As can be seen from FIG. 1 showing the analysis result, the inorganic fiber was composed of an inner layer portion and a surface layer portion formed at a point of about 20 nm from the fiber surface. The proportion of elements forming the inner layer portion was 51% silicon, 29% carbon, 18% oxygen, and 2% titanium. In the surface layer,
From the point of about 20 nm from the fiber surface, the ratio of carbon increased to 80% of the outermost surface from the point of about 20 nm toward the fiber surface, while the ratios of silicon, oxygen and titanium gradually decreased. The tensile strength of this inorganic fiber is 330 kg / mm ² , and the elastic modulus (measured by the strand method) is 18 t / mm.
It was ² .

Reference Example 2 Polyzirconocarbosilane was prepared in the same manner as in Reference Example 1 except that 30 parts of zirconium tetrabutoxide was used instead of titanium tetrabutoxide. Using this polyzirconocarbosilane, in the same manner as in Reference Example 1, spinning, infusibilization, and then firing to obtain a diameter of 12 μm.
m inorganic fibers were obtained. This inorganic fiber is composed of an inner layer part and a surface layer part formed at a point of about 25 nm from the fiber surface, and the ratio of the constituent elements of the inner layer part is silicon 53.
%, Carbon 28%, oxygen 17% and zirconium 2%. It was observed that the proportion of carbon in the surface layer portion increased to 85% of the outermost surface, and the proportions of silicon, oxygen and zirconium gradually decreased. The tensile strength of this inorganic fiber was 315 kg / mm ² , and the elastic modulus (measured by the strand method) was 18 t / mm ² .

Reference Example 3 The infusible fiber of Reference Example 1 was fired at 1300 ° C. without a temperature gradient in a firing furnace to give a diameter of 12 μm.
The inorganic fiber of was obtained. The result of composition analysis from the surface of this inorganic fiber to the fiber axis direction is shown in FIG. As can be seen from FIG. 2, this inorganic fiber has a uniform composition throughout, and the ratio of constituent elements is 50% silicon, 30% carbon, 18% oxygen.
And titanium 2%. The tensile strength of this inorganic fiber is 3
It was 35 kg / mm ² and the elastic modulus (measured by the strand method) was 18 t / mm ² .

Example 1 Y ₂ O ₃ and A were added to silicon nitride powder having an average particle size of 0.8 μm.
5% of 1 ₂ O ₃ was added to each, and 10% of polyvinyl alcohol was further added as a binder, followed by ball mill mixing in a mixed solvent of ethanol and distilled water for 48 hours to prepare a slurry of a matrix raw material. Reference example 1
After continuously pressing the bundle of inorganic fibers (800 filaments) obtained in step 2 onto several Teflon cylindrical pins,
Air was blown to open the fiber to a width of about 1.5 cm. The opened inorganic fibers were wound on a drum to prepare a unidirectional sheet of inorganic fibers. The sheet was dipped in the matrix raw material slurry and then sufficiently dried to prepare a prepreg sheet. This prepreg sheet is 5 cm x 5 cm x 5
After being cut into a square of cm, they were laminated in a graphite die coated with colloidal carbon as a release agent, and hot pressed at a temperature of 1000 ° C. and a pressure of 300 kg / cm ² in an argon atmosphere. After hot-pressed product is coated with boron nitride, tantalum foil is wrapped and vacuum-encapsulated in a Pyrex glass capsule at a temperature of 1700 ° C and a pressure of 1000.
Hot isostatic pressing was performed at kg / cm ² to obtain an inorganic fiber reinforced ceramics composite material having silicon nitride as a matrix. The proportion of inorganic fibers in the composite material was 50% by volume. The bending strength of this composite material is 150 kg / mm at room temperature.
² , 100 kg / mm ² at 1400 ° C., the fracture toughness value was 13.5 MPa · m ^1/2 , which was about twice that of the sintered body containing only silicon nitride. As a result of observing the fracture surface of this composite material with a scanning electron microscope, it was found that an interface layer made of a mixture of carbon and carbide was formed between the fiber and the matrix as shown in FIG.

Comparative Example 1 A composite material was obtained by repeating Example 1 except that the fiber obtained in Reference Example 3 was used in place of the fiber obtained in Reference Example 1. The bending strength of this composite material is 60 kg / m at room temperature.
m ² was 40 kg / mm ² at 1400 ° C. As a result of observing the fracture surface of this composite material with a scanning electron microscope, it was found that the fibers in the composite material violently reacted with the matrix as shown in FIG.

Example 2 10% of polyethylene oxide as a binder was added to alumina powder having an average particle size of 0.4 μm, and ball mill mixing was performed for 40 hours in a mixed solvent of ethanol and water to prepare a matrix raw material slurry. did. The matrix raw material slurry was placed in a tank equipped with a bubbling device, the inorganic fiber bundle obtained in Reference Example 1 was immersed in this slurry, and the matrix slurry was attached to each fiber simultaneously with the fiber opening by bubbling. .. Then, the fiber bundle to which the slurry was attached was wound around a drum and sufficiently dried to produce a prepreg sheet. This prepreg sheet was cut into a square of 5 cm × 5 cm × 5 cm, and then laminated in a graphite die coated with boron nitride as a release agent, and the temperature was 1400 ° C. under an argon atmosphere at a pressure of 5
Hot pressing was performed at 00 kg / cm ² to obtain an inorganic fiber reinforced composite material having alumina as a matrix. The proportion of inorganic fibers in the composite material was 50% by volume. The bending strength of this composite material is 170 kg / mm ² , 1300 ° C at room temperature.
Is 100 kg / mm ² and the fracture toughness value is 17.5 M
Pa · m ^1/2 , which was about 5.5 times that of the sintered body containing only alumina.

Example 3 Example 2 was repeated, except that the inorganic fiber obtained in Reference Example 2 was used instead of the inorganic fiber obtained in Reference Example 1, to obtain an inorganic fiber reinforced composite material containing alumina as a matrix. Obtained. The bending strength of this composite material is 165 kg / mm at room temperature.
² was 105 kg / mm ² at 1300 ° C., and the fracture toughness value was 14 MPa · m ^1/2 .

Example 4 After adding 7% of polyvinylyl alcohol as a binder to mullite powder having an average particle diameter of 1.5 μm, ball mill mixing was performed for 45 hours in a mixed solvent of ethanol and water to prepare a matrix raw material slurry. Prepared. Then, the prepreg sheet was prepared and hot pressed in the same manner as in Example 2 to obtain an inorganic fiber-reinforced composite material having mullite as a matrix. The proportion of inorganic fibers in the composite material was 45% by volume. The bending strength of this composite material is 105 kg / mm ^{2 at} room temperature and 80 kg / mm at 1400 ° C.
² , the fracture toughness value is 16 MPa · m _1/2 ,
It was about 6.5 times that of the sintered body containing only alumina.

Example 5 Calcium carbonate, magnesium oxide and silicon dioxide are mixed in a weight ratio of 1: 1: 2, and the mixture is 1500-155.
The glass obtained by melting at 0 ° C. and then rapidly cooling in water was pulverized to 3 μm or less to prepare a glass powder. The inorganic fiber obtained in Reference Example 1 was embedded in this glass powder, and a graphite mold was used to press the inorganic fiber under pressure of 200 kg / cm ^2.
Hot pressing was performed at 300 ° C. for 1 hour to obtain a fiber-reinforced glass composite material having a fiber content of 20% by volume. The bending strength of this glass composite material was 80 kg / mm ² . Further, this glass composite material was bent at 72 kg / mm ² even after repeating 5 times the heat cycle in which the composite material was put in a furnace kept at 1000 ° C., rapidly heated for 30 minutes, taken out, and forcedly cooled for 30 minutes. The strength was retained (flexural strength retention rate: 90%).

Example 6 Magnesium oxide, aluminum oxide and silicon dioxide were mixed in a weight ratio of 4:10:15, 8% of titanium oxide was added, and the mixture was melted in air at about 1600 ° C. The glass was produced by taking it out into the air at room temperature. This glass was crushed to 100 μm or less and 1 μm or more to prepare glass powder. After adding 10% of polyethylene oxide as a binder to this glass powder, it was ball-milled for 40 hours in a mixed solvent of ethanol and water to prepare a matrix raw material slurry. After that, a prepreg sheet was produced in the same manner as in Example 2. This prepreg sheet is 5 cm x 5
After being cut into a square of 5 cm × 5 cm, it is laminated in a graphite die coated with colloidal carbon as a release agent, and the temperature is 1100 to 1150 ° C. in an argon atmosphere at a pressure of 50.
It was hot pressed at kg / cm ² . After that, the pressing pressure was returned to normal pressure, and heat treatment was performed at a temperature of 1250 ° C. for 1 hour to crystallize to obtain an inorganic fiber reinforced composite material having crystallized glass as a matrix. The ratio of inorganic fibers in the composite material is 4
At 5% by volume, the crystalline phases in the matrix were cordierite and cristobalite. The bending strength of this composite material is 80 kg / mm ² at room temperature, and the fracture toughness value is 18 M.
It was Pa · m ^1/2 .

[0023]

[Brief description of drawings]

FIG. 1 is a diagram showing a composition analysis result of inorganic long fibers obtained in Reference Example 1.

FIG. 2 is a diagram showing a composition analysis result of inorganic long fibers obtained in Reference Example 3.

FIG. 3 is a transmission electron micrograph and an energy dispersive X-ray spectroscopic analysis showing a composite structure in the vicinity of an interface between a fiber and a matrix in the composite material obtained in Example 1.

FIG. 4 is a scanning electron micrograph fiber structure of a fracture surface of the composite material obtained in Comparative Example 1.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshikatsu Harada 5 1978, Kogushi, Ube City, Ube Yamaguchi Prefecture Ube Kosan Co., Ltd.

Claims (1)

[Claims] 1. An inorganic fiber-reinforced ceramic composite material comprising inorganic fibers as a reinforcing material and ceramics as a matrix, wherein the inorganic fibers are 40 to 60% by weight of silicon and 20 to 40 carbon.
% By weight, 0.5 to 10% by weight of titanium or zirconium,
And an inner layer portion consisting of 10 to 30% by weight of oxygen, and silicon 0.
˜40% by weight, carbon 50 to 100% by weight, titanium or zirconium 0 to 8% by weight, and oxygen 0 to 25% by weight, and the carbon content is 50% from the surface.
The surface layer portion formed in the region of 0 nm or less has a composition distribution that gradually increases toward the fiber surface, and the inorganic fiber is (1) composed of silicon, carbon, titanium or zirconium, and oxygen. (2) β-SiC, MC, C, a solid solution of β-SiC and MC, and at least one selected from the group consisting of MC _1-x , and a crystalline material having a particle size of 50 nm or less. An aggregate comprising fine particles and amorphous SiO ₂ and MO ₂ , or (3) a mixture of the amorphous substance of (1) above and the aggregate of (2) above (wherein M is titanium or Zirconium,
x is a number greater than 0 and less than 1. ) Inorganic fiber reinforced ceramics composite material characterized by being comprised.