JP2000026170A - Ceramic composite material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a ceramic composite material having high strength and airtightness without forming a porous part that causes defects. SOLUTION: The reinforcing material forming body of the ceramic composite material 1 comprises a three-dimensional rectangular solid formed by laminating two-dimensional fabrics 11 woven from yarn obtd. by twisting ceramic fibers in the Z-axis direction. In each two-dimensional fabric 11C disposed at the central part of the solid, both the warp 10B and the woof 10H are close woven at the central part and are loosen toward the edges. In the upper two-dimensional fabric 11U and the lower two-dimensional fabric 11L, the warp 10B and the woof 10H are loosely woven all over the entire surface.

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 obtained by reinforcing a ceramic base material with a reinforcing material made of a ceramic fiber fabric.

[0002]

2. Description of the Related Art A ceramic composite material (CMC) formed by reinforcing a ceramic base material with a reinforcing material formed by weaving a yarn formed by twisting ceramic fibers.
ix Composites) is manufactured by polymer impregnation and firing method: PIP (Polymer Impregnation and Pirolysis).
And gas phase impregnation method: CVI (Chemical Vapor Infiltratio)
n) is known.

In the polymer impregnation firing method, for example, a reinforcing material made of ceramic fibers is immersed in a solution obtained by dissolving an organosilicon polymer such as polycarbosilane in a solvent such as xylene to impregnate the polymer between the woven yarns. After drying,
It is to be fired at a high temperature to form a silicon carbide base material.

[0004] In the gas phase impregnation method, a fabric made of ceramic fibers as a reinforcing material is heated to a high temperature in a furnace, and a silicon carbide base material is formed in a reduced pressure atmosphere. For example, thermal decomposition of methyltrichlorosilane gas is used for the deposition of silicon carbide.

[0005]

However, in the case of the ceramic composite material formed by the above-described method, if the reinforcing material is formed with a narrow and dense yarn interval for the purpose of improving the strength and airtightness, the impregnation of the base material is prevented. However, there is a problem that pores in which a parent phase is not formed remain inside due to deterioration of properties. Such pores may cause defects during use.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a ceramic composite material having high strength and airtightness without formation of pores which induce defects.

[0007]

A ceramic composite material according to the present invention, which achieves the above object, is a ceramic composite material comprising a ceramic base material reinforced by a reinforcing material made of a ceramic fiber woven fabric, wherein the yarn spacing of the reinforcing material is reduced. ,
It is characterized in that the parts requiring airtightness are set densely and the other parts are set roughly.

Further, in a ceramic composite material obtained by reinforcing a ceramic base material with a reinforcing material made of a ceramic fiber fabric, the yarn spacing of the reinforcing material is set densely on the inside and coarse on the outer surface. And

Further, in addition to the above configuration, the reinforcing member is characterized in that the thickness of the yarn in at least one direction is set to be thick at a portion where the yarn interval is coarse, corresponding to the yarn interval. .

In a ceramic composite material which is formed in a cylindrical shape by reinforcing a ceramic base material with a reinforcing material made of a ceramic fiber woven fabric, the reinforcing material is formed in multiple layers in the thickness direction by blade weaving. The interval is set densely on the inner peripheral surface side and coarsely set on the outer peripheral surface side.

The thickness of the yarn corresponds to the density of the yarn, and the yarn is set to be thick at a portion where the yarn is coarse.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a perspective view conceptually showing a reinforcing material molded body 10 as a reinforcing material made of a ceramic fiber fabric in one configuration example of the ceramic composite material according to the present invention. Note that this configuration example is an example of three-dimensional weaving, but can be applied to a laminated material or two-dimensional weaving material that is two-dimensional weaving.

The illustrated reinforcing material forming body 10 is made of a cloth-shaped two-dimensional woven fabric 11 in which yarns formed by twisting ceramic fibers such as silicon carbide are plain-woven (woven yarns are arranged orthogonally in the X-axis and Y-axis directions). The layers are stacked in the Z-axis direction and connected by a weaving thread (not shown) in the height direction to form a three-dimensional solid (a rectangular parallelepiped). A matrix is formed by impregnating a ceramic base material such as silicon carbide into the voids between the yarns of the reinforcing material molded body 10 by a polymer impregnation firing method (PIP) or a gas phase impregnation method (CVI), and forming a diamond grindstone or the like. The outer shape is processed into a predetermined shape to obtain a completed ceramic composite material 1.

Here, each two-dimensional fabric 11 laminated in the Z-axis direction of the reinforcing material molded body 10 has its warp 10B and weft 1
The interval of 0H differs according to the position in the Z-axis direction. That is, the two-dimensional fabric 11C disposed at the center is the same as that of FIG.
As shown in (A), the two-dimensional fabrics 11U and 11L in which the central portions of both the warp 10B and the weft 10H are denser and coarser toward the outer edge side and are disposed on the upper and lower outer surfaces are shown in FIG.
As shown in (B), the interval between the warp yarn 10B and the weft yarn 10H is formed coarsely over the entire surface. The two-dimensional woven fabrics 11M... Located between them are formed such that the interval between the warp yarns and the weft yarns gradually changes in an intermediate state between the two (so that the central portion gradually becomes coarser). Further, the arrangement of the two-dimensional fabric 11 in the Z-axis direction is set such that the center thereof is dense and the two-dimensional fabric 11 is roughened toward the upper and lower outer surfaces.

Thus, in the reinforcing material molded body 10 configured as described above, the arrangement of the yarns is such that the center of the yarns is denser in any direction of the X, Y, and Z axes, and is closer to the outer peripheral surface. It is rough. For this reason, the gap between the yarns is large on the outer peripheral surface and small at the center, and when impregnating the base material, a matrix is formed in a small space between the yarns in the central portion and sequentially in a large space on the outer peripheral surface side. As a result, it is possible to prevent the defects caused by the remaining pores without leaving any pores inside, and to obtain the ceramic composite material 1 having high strength and high airtightness.

In the above configuration example, the reinforcing material molded body 10 is formed by laminating two-dimensional plain woven fabrics 11.
The structure of the reinforcing material molded body 10 is not limited to plain weave,
Further, the woven yarn to be made dense and coarse may be only one of the warp and the weft.

Further, in the above configuration, all the two-dimensional fabrics 1
When 1 is formed by using the same thickness woven yarn, the strength of the ceramic composite material 1 is reduced at a portion where the yarn spacing is coarse because the reinforcing material density is low,
This can be solved by changing the diameter of the yarn at each portion (that is, increasing the diameter of the yarn at a portion where the yarn interval is coarse).
In other words, in a portion where the yarn interval is coarse and the yarn density is low, the number of fibers forming the yarn is increased (the yarn is made thicker).
By increasing the fiber density, the strength of the entire ceramic composite material 1 can be made constant.

FIG. 3 is a perspective view conceptually showing a reinforcing material molded body of a ceramic composite material having a configuration example different from the above.
The illustrated reinforcing material molded body 10 'is an example of a ceramic composite material 1' which requires high airtightness on the lower surface side.

The reinforcing material molded body 10 'is formed by laminating a two-dimensional woven fabric 11' formed by plain weaving a yarn formed by twisting ceramic fibers such as silicon carbide in the Z-axis direction and having a height (not shown), as in the above configuration example. It is formed into a three-dimensional solid (rectangular parallelepiped) by binding with the weaving yarns in the directions.

The two-dimensional woven fabric 11L 'located on the lower surface side
4A, both the warp and the weft are formed densely as shown in FIG. 4 (A), and the two-dimensional woven fabric 11U ′ located on the upper surface side has both the warp 10B and the weft 10H as shown in FIG. 4 (B). Two-dimensional fabric 1 which is formed coarsely and is located between them
1M 'is formed such that the spacing between the warp yarns of the warp yarn 10B and the weft yarn 10H gradually changes in an intermediate state between them. Further, the arrangement intervals in the z-axis direction of the two-dimensional fabrics 11 'are arranged to be coarser toward the upper surface side. Furthermore, the thickness (the number of reinforcing fibers) of the yarns of each two-dimensional woven fabric 11 'corresponds to the density of the inter-woven yarns. ), And the amount of reinforcing fibers per unit volume is set to be constant.

Reinforcement molding 1 constructed as described above
In 1 ', when the base material is impregnated, a matrix phase is initially formed on the lower surface side where the dense two-dimensional fabric 11L' is disposed, and the base material is not impregnated from the lower surface side, but is coarse. The base material is impregnated from the upper surface side on which the two-dimensional fabric 11U 'is disposed, and the ceramic composite material 1' in which the base phase is formed as a whole can be obtained. Thereby, the lower surface side is smooth and highly airtight, and the amount of reinforcing fibers per unit volume is equal in each part, so that the ceramic composite material 1 'having a constant strength can be constituted. The surface on which the warp and the weft are densely formed (the two-dimensional fabric 11L ') is not limited to the lower surface and may be provided at any position in the height direction.

FIG. 5 is a cross-sectional view of a reinforcing material forming body of a configuration example in which a cylindrical ceramic composite material 2 requiring smooth and high airtightness on the inner peripheral surface is formed.

As shown conceptually in FIG. 6, the illustrated reinforcing material forming body 20 has left and right braided yarns 22 obliquely inclined in opposite directions with respect to a plurality of axially extending central yarns 21 arranged in the circumferential direction. The tissue by blade weaving that is woven in two is provided concentrically and double (the inner peripheral tissue 20A and the outer peripheral tissue 2A).
0B) is formed.

The thickness of the braided yarn 22 is equal in the inner circumferential side structure 20A and the outer circumferential side structure 20B.
0A central thread 21A is arranged finely and densely,
The central thread 21B of 0B is thickly and coarsely arranged in the circumferential direction. That is, the thickness (the number of reinforcing fibers) of the center yarn 21 corresponds to the density in the circumferential direction, and is thin (the reinforcing fiber amount is small in the dense inner peripheral structure 20A) and thick (reinforcement) in the coarse outer structure 20B. (The amount of fibers is large) and the amount of reinforcing fibers per unit volume is set to be constant.

The reinforcing member formed body 20 formed as described above
Then, when the base material is impregnated, a matrix phase is initially formed in the inner circumferential side structure 20A where the central yarn 21A is dense, and the base material is not impregnated from the inner circumferential side. The base material is impregnated with the base material from the (outer side structure 20B side), and the cylindrical ceramic composite material 2 in which the whole parent phase is formed can be obtained. Thereby, the inner peripheral surface side is smooth and has high airtightness, and the amount of reinforcing fibers per unit volume can form the ceramic composite material 2 having the same strength at each portion.

In this embodiment, the central thread 21A of the inner side structure 20A is densely arranged in order to obtain a smooth and high air-tightness on the inner peripheral surface side. If the central thread 21B of the side structure 20B is densely arranged, the outer peripheral surface side can be configured to be smooth and highly airtight. In the above configuration example, the structure of the blade weave (the inner circumferential structure 20A and the outer circumferential structure 20B) is double-polymerized, but the present invention is not limited to this, and the structure may be triple or more. Further, the tissue structure of the cylindrical reinforcing material formed body is not limited to blade weave, for example, by bending a two-dimensional woven fabric of plain weave as in the above configuration example and joining both ends to form a cylindrical structure. It may be formed in the form.

[0027]

As described above, according to the ceramic composite material according to the present invention, the space between the reinforcing yarns is set so that the portion requiring airtightness is set densely and the other portions are set coarse. Then, the impregnation of the base material is performed in the dense portion through the portion in which the yarn spacing is coarse, and progresses from the dense portion to the coarse portion. For this reason, a ceramic composite material having high strength and airtightness can be formed without leaving pores even in a portion where the yarn spacing is close.

Further, the weaving yarn spacing of the reinforcing material is dense inside,
By setting the outer surface to be rough, it is easy to impregnate the base material from the outside to the inside, and it is possible to obtain a ceramic composite material with high strength and airtightness without residual pores that induce defects. is there.

The reinforcing material has a thickness of the weaving yarn in at least one direction corresponding to the yarn spacing, and is set thick at a portion where the yarn spacing is coarse. The same strength can be set in each part, and the entire strength can be configured to be constant.

Further, the cylindrical reinforcing material is formed in multiple layers in the thickness direction by blade weaving, and the spacing between the yarns is set densely on the inner peripheral surface side and coarsely on the outer peripheral surface side. The impregnation of the base material was performed on the dense inner peripheral surface side via the outer peripheral surface side where the weave yarn interval was coarse, and an airtight parent phase without pores was formed even on the inner peripheral surface side where the weave yarn interval was dense. It can be made of a cylindrical ceramic composite material.

Further, the thickness of the weaving yarn corresponds to the density of the interval, and the amount of the reinforcing fiber per unit volume is set to be equal at each portion by setting the thickness at the portion where the interval between the yarns is coarse. And the strength of the whole can be made constant.

[Brief description of the drawings]

FIG. 1 is a perspective view conceptually showing a reinforcing material molded body in one configuration example of a ceramic composite material according to the present invention.

FIG. 2 is a plan view of a two-dimensional fabric forming the reinforcing material molded body of FIG. 1, wherein (A) is a two-dimensional fabric disposed in the center,
(B) is a two-dimensional woven fabric disposed on the upper and lower outer surfaces.

FIG. 3 is a view conceptually showing a reinforcing material molded body in another configuration example.

FIGS. 4A and 4B are plan views of a two-dimensional fabric forming the reinforcing material molded body of FIG. 1, wherein FIG. 4A is a two-dimensional fabric disposed on the lower surface side, and FIG. It is a two-dimensional fabric.

FIG. 5 is a cross-sectional view of a reinforcing member forming body of a configuration example for forming a cylindrical ceramic composite material.

FIG. 6 is a conceptual diagram illustrating blade weaving.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ceramic composite material 2 Ceramic composite material 10 Reinforcement molding (reinforcement) 10B Warp (woven yarn) 10H Weft (woven yarn) 10 'Reinforcement molding (reinforcement) 20 Reinforcement formation (reinforcement) 21 Center Yarn (woven yarn) 22 Braided yarn (woven yarn)

Claims (5)

[Claims] 1. A ceramic composite material obtained by reinforcing a ceramic base material with a reinforcing material made of a ceramic fiber woven fabric, wherein the yarn spacing of the reinforcing material is tight in a portion requiring airtightness,
A ceramic composite material characterized in that other parts are roughly set. 2. A ceramic composite material in which a ceramic base material is reinforced by a reinforcing material made of a ceramic fiber woven fabric, wherein the yarn spacing of the reinforcing material is set densely on the inside and coarse on the outer surface side. Ceramic composite material. 3. The reinforcing material according to claim 1, wherein the thickness of the weaving yarn in at least one direction is set to be thick at a portion where the yarn yarn interval is coarse, corresponding to the yarn yarn interval.
2. The ceramic composite material according to item 1. 4. A ceramic composite material formed into a cylindrical shape by reinforcing a ceramic base material with a reinforcing material made of a ceramic fiber woven fabric, wherein the reinforcing material is formed in multiple layers in the thickness direction by blade weaving. A ceramic composite material, wherein the interval is set densely on the inner peripheral side and coarsely set on the outer peripheral side. 5. The ceramic composite material according to claim 4, wherein the thickness of the yarn corresponds to the density of the yarn, and the yarn is set thick at a portion where the yarn is coarse.