JPH11217273A - Production of fiber-reinforced ceramic-based composite material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently produce a composite material having a high fracture energy without providing a heat damage to a reinforcing fiber at a short time by thermally spraying a ceramic material to the reinforcing fiber previously arranged in a prescribed position or shape to form a ceramic mother phase. SOLUTION: A carbon fiber, a ceramic fiber, a metal fiber or the like is oriented in uniaxial one dimensional, or two or more multiaxial two dimensional orientation to provide a reinforcing fiber. The reinforcing fibers are arranged on a metallic substrate, and a ceramic material such as an oxide ceramic such as alumina is thermally sprayed thereon. The thermally sprayed material in a molten state at a high temperature is quenched on the reinforcing fibers and accumulated to form a ceramic mother phase. Any of a plasma spraying, a glass-field flame spraying, a high-velocity flame spraying, an explosion spraying and a wire explosion spraying are suitable for the thermal spray method. A plurality of composite layers formed by repeating the method to laminate the layers and having a prescribed thickness is taken out from the substrate, and subjected to a necessary heat treatment and machine work to provide the objective fiber-reinforced ceramic-based composite material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a composite material in which a ceramic matrix is reinforced with continuous fibers in order to suppress the tendency of ceramics to brittle fracture.

[0002]

2. Description of the Related Art In the production of a ceramic matrix composite material, a green compact in which reinforcing fibers are arranged in a matrix material (usually a powder) is obtained by various methods, and finally a normal ceramic sintering is performed. As in the manufacture of the body, it is common to bake at high temperatures. In such a method, the ceramic, which is a high melting point material, becomes the matrix,
To obtain a dense sintered body, the green compact must be heated to 1000 ° C.
It is necessary to fire at the above high temperature. For this reason, the reinforcing fibers are exposed to high temperatures during firing, and are damaged, and the performance of the sintered body tends to deteriorate, and it has been difficult to produce a composite material having excellent properties. Also, the composite fiber is
Since the sintering of the matrix ceramic is easily suppressed, a hot press method or the like is often used in order to accelerate the sintering by applying an external pressure during sintering. However, since this method is a uniaxial pressing method, only a composite material having a simple shape can be manufactured, and wide application of this kind of composite material is hindered.

[0003] For the purpose of producing a composite material under relatively low temperature conditions, a CVI method in which a gas is used as a matrix material to generate a matrix by a chemical reaction, and a polymer precursor for obtaining ceramics by thermal decomposition of organic substances Methods such as the law have also been tried. However, these methods require a long time in the manufacturing process, require a route for introducing a raw material gas or discharging a decomposition product gas, and thus it is difficult to obtain a dense composite, However, there are problems such as the necessity of extremely large and expensive production equipment compared to the size of the material, and the fact that toxic gases are often used or exhausted during production, and the material cost tends to be extremely high. doing. Therefore, these points have also been a serious obstacle to wide application of such composite materials.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a new method for producing a fiber-reinforced ceramic-based composite material in a short time and with little damage to reinforcing fibers.

[0005]

Means for Solving the Problems The present inventor has conducted various studies to achieve the above-mentioned object, and as a result, a ceramic matrix was formed on a reinforcing fiber arranged in a predetermined position or shape in advance by a thermal spraying method. It has been found that by adding the raw materials, a desired fiber-reinforced ceramic-based composite material can be produced with almost no damage to the fibers, and the present invention has been completed.

That is, the present invention provides the following method for producing a fiber-reinforced ceramic-based composite material.

[0007] 1. A method for producing a fiber-reinforced ceramic matrix composite material comprising a reinforcing fiber and a ceramic matrix, wherein the ceramic matrix is generated by a thermal spraying method.

[0008] 2. Item 2. The method for producing a composite material according to Item 1, wherein the ceramic matrix is an oxide ceramic.

3. Item 3. The method for producing a composite material according to Item 1 or 2, wherein the reinforcing fibers are at least one of carbon fibers, ceramic fibers, and metal fibers.

[0010] 4. Item 4. The method for producing a composite material according to any one of Items 1, 2 and 3, wherein the reinforcing fibers are uniaxially and one-dimensionally or multiaxially and two-dimensionally or multiaxially oriented.

5. 5. The production of a composite material according to any one of the above items 1 to 4, which uses any one of plasma spraying, gas combustion flame spraying, high-speed flame spraying, explosive spraying and wire explosion spraying as a spraying method for forming a matrix ceramic. Method.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a thermal spraying method for forming a ceramic matrix is not particularly limited, and various methods such as a plasma spraying method, a flame spraying method, an explosive spraying method, and a line explosive spraying method are exemplified. Can be These methods are well-known techniques and will not be described in detail.For example, in the plasma spraying method, a powder material of several tens of μm is charged into a DC arc plasma jet, and the powder is instantaneously melted by the heat of the plasma. This is a method in which a coating is formed by accelerating and spraying the object to be coated with a high-speed gas jet and solidifying and depositing on the surface. This method uses powder (which is used as a matrix material in the present invention) as a thermal spraying material, so it can form a film at a significantly higher speed than CVD, PVD, etc. This is the technology used.

[0013] When the plasma spraying method is carried out, the ceramic powder is heated to a molten state and brought to a very high temperature state. However, since the individual particles are fine and the heat capacity is small,
It is quenched during deposition on the reinforcing fibers and causes little thermal damage to the fibers.

The same applies to the case of forming a matrix ceramic by another spraying method, but the optimum particle size of the raw material powder is determined according to each method and / or the type of ceramic material to be formed. Selection and, if necessary, adjustment of conditions such as optimizing thermal spraying conditions using a linear or rod-shaped raw material may be performed. Such choices and adjustments
Those skilled in the art can appropriately do so.

The ceramic material for forming the matrix in the composite material is not particularly limited. For example, as the oxide material, an oxide of a single metal such as alumina, zirconia, titania, and magnesia; a double metal oxide such as spinel, mullite, and zircon; and an oxide glass such as borosilicate glass and quartz glass are used. it can. Also, chromium carbide,
Non-oxide materials such as tungsten carbide, zirconium boride, titanium boride and the like can also be used.

The reinforcing fibers are not particularly limited, and include, for example, carbon fibers; silicon carbide, alumina, zirconia,
Ceramic fibers such as SiTiCO; metal fibers such as molybdenum, tantalum, and inconel can be used.

The shape and size of the fibers are also long fibers, and have a length that penetrates the composite material in a predetermined direction.
If the means for arranging at appropriate intervals can be applied,
There is no particular limitation, as long as it is a uniaxial one-dimensional, two- or more-axial multiaxial two-dimensional oriented fiber. More specifically, a monofilament, a yarn, a two-dimensional knitted fabric, a nonwoven fabric, or the like can be used.

In the method of the present invention, a composite material is usually formed on a metal substrate (a flat plate, a flat plate assembled into a prismatic shape, a pipe, etc.) having substantially the same coefficient of thermal expansion as the matrix material in the following order. . Examples of the metal base material selected according to the type of the matrix material include ordinary steel, stainless steel, and Invar alloy.

(1) If necessary, a matrix ceramic layer having a predetermined thickness is formed on a base material by a thermal spraying method in consideration of an inner finish polishing margin.

(2) The reinforcing fibers are arranged and fixed on the matrix ceramic layer formed as described above while applying tension at predetermined intervals. (If the base material is in the shape of a prism or a pipe, winding is performed. It is valid).

(3) A matrix ceramic layer having a predetermined thickness is formed on the reinforcing fiber layer formed above by a thermal spraying method.

(4) Until the thickness of the composite reaches a predetermined value,
The operations (2) and (3) are alternately repeated as appropriate.

(5) In the final thermal spraying operation, a matrix ceramic layer having a predetermined thickness is formed on the fiber layer in consideration of an outer finish polishing margin, if necessary.

(6) Next, the composite is removed from the metal substrate by mechanical or chemical means.

(7) If necessary, a heat treatment is performed on the composite to release stress, change the crystal phase due to phase transformation, and increase the density.

(8) If necessary, finish polishing the inner and outer surfaces to finish the composite material to predetermined dimensions.

[0027]

According to the method of the present invention, since the matrix is formed by rapidly solidifying and laminating the raw material particles having a very small heat capacity, the performance of the reinforcing fibers hardly deteriorates due to thermal damage. There is no.

Further, if necessary, the temperature of the composite material can be kept close to room temperature by blowing compressed air on the composite material in the course of forming or by cooling the substrate with water. Even with this method, the deterioration of the reinforcing fiber can be suppressed to a minimum, so that the properties such as the original strength and elastic modulus of the reinforcing fiber can be sufficiently exhibited in the composite material.

According to the method of the present invention, the thickness of the matrix ceramic layer between the reinforcing fiber layers is adjusted by adjusting the amount of powder charged, the moving speed of the thermal spray gun, the number of times of thermal spraying, and the like, as in the case of normal thermal spraying. Can be controlled relatively easily, so that the fiber content in the composite material can be easily controlled.

Furthermore, in the method of the present invention, since there is no limitation due to the inner volume of the electric furnace, the composite material to be produced has almost no dimensional restrictions.

Further, in the method of the present invention, unlike in the case of the sintering method, since the volume shrinkage of the composite during the manufacturing process is almost nil, the composite having the required dimensions can be obtained with high precision.

[0032]

The following examples are provided to further clarify the features of the present invention.

EXAMPLE 1 Six flat plates of 40 mm × 40 mm × 3 mm general structural steel (SS400) were assembled in a hexagonal column shape, and a composite material was produced by plasma spray molding using this as a base material. Silicon carbide fiber is used as the reinforcing fiber, and the average particle size is used as the matrix ceramic material.
20 μm alumina powder for thermal spraying was used.

On the outer surface of the substrate, a matrix ceramic layer of about 400
The process of spraying μm, and winding a bundle (length 5 m) of about 250 fibers (diameter 15 μm) twisted at intervals of 2 mm thereon, and spraying the matrix ceramic layer again thereon was repeated five times.

Next, the obtained composite material is cut into six plates, the composite material on the base material is immersed in hydrochloric acid, and the base material is dissolved to obtain five fiber layers and six matrix ceramic layers. And 6 composite plates each having a thickness of about 3 mm were prepared.

Next, a test piece was cut out in the fiber longitudinal direction of the obtained composite plate, and a three-point bending strength test according to JIS R1601 and measurement of fracture toughness and fracture energy by SENB (Single Edged Notched Bend Beam) method were performed. Then, the physical properties of the composite were evaluated. Table 1 shows the results. FIG. 1 shows a load-displacement diagram of the composite material in the bending test.

Comparative Example 1 A sprayed alumina film having a thickness of about 3 mm was formed on the same base material as in Example 1, and the bending strength, fracture toughness and fracture energy were measured in the same manner as in Example 1. The results are shown in Table 1. FIG. 1 also shows a load-displacement diagram of the material in the bending test.

[0038]

[Table 1]

The results shown in Table 1 show that in the composite according to the present invention, the other properties are almost unchanged, only the fracture energy is increased by about 70 times, and the brittle fracture is suppressed. I have. This confirms that the composite is formed without damaging the reinforcing fibers.

[Brief description of the drawings]

FIG. 1 is a graph showing a weight-displacement diagram of the composite materials obtained in Example 1 and Comparative Example 1.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masato Suzuki 1-81-31 Midorioka, Ikeda-shi, Osaka Inside the Industrial Technology Research Institute Osaka Institute of Technology (72) Inventor Isao Kondo 1--8-3 Midorioka, Ikeda-shi, Osaka No. 31 in Osaka Institute of Technology

Claims (5)

[Claims] 1. A method for producing a fiber-reinforced ceramic matrix composite comprising a reinforcing fiber and a ceramic matrix,
A method for producing a composite material, wherein a ceramic matrix is formed by a thermal spraying method. 2. The method according to claim 1, wherein the ceramic matrix is an oxide ceramic. 3. The method according to claim 1, wherein the reinforcing fiber is at least one of carbon fiber, ceramic fiber and metal fiber. 4. The method for producing a composite material according to claim 1, wherein the reinforcing fibers are oriented uniaxially one-dimensionally or multiaxially two-dimensionally with two or more axes. 5. The method according to claim 1, wherein any one of plasma spraying, gas-fired flame spraying, high-speed flame spraying, explosive spraying and linear explosion spraying is used as the spraying method for forming the matrix ceramic. Of manufacturing a composite material.