JPH0791121B2 - Method and apparatus for producing three-dimensional fiber-reinforced ceramic matrix composite material - Google Patents

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 three-dimensional fiber reinforced ceramic matrix composite material and an apparatus therefor.

[0002]

2. Description of the Related Art Fiber-reinforced ceramic matrix composite materials have recently attracted attention as ones for improving the fatal defects of conventional simple ceramics, that is, low toughness and low strength reliability. became. This type of fiber reinforced composite material has one-dimensional reinforcement in which the fibers are arranged in only one direction, two-dimensional reinforcement in which the fibers are arranged in two directions (planar arrangement), and three-dimensional arrangement ( It can be divided into three types of three-dimensional reinforcement (three-dimensional arrangement). In the case of one-dimensional reinforcement, the tensile and bending strengths are strong in the fiber direction, but weak in the direction perpendicular to the fiber. Also, 2
In the case of dimensional reinforcement, although the strength in the plane in which the fibers are arranged is large, the strength in the direction perpendicular thereto is small, and peeling easily occurs. However, in the case of three-dimensional strengthening, the strength in any direction is almost equal and isotropic. Therefore,
When using fiber-reinforced composite materials as structural materials, three-dimensional reinforcement is most ideal.

Fabrication of fiber reinforced ceramic matrix composites is relatively easy for 1 and 2 dimensional reinforcement, but very difficult for 3 dimensional reinforcement and involves some problems that must be solved. I'm out. A problem in the method for producing a three-dimensional fiber-reinforced ceramic matrix composite material is basically to fill the fiber gaps of a three-dimensionally woven fiber preform with a ceramic serving as a matrix. However, unlike the one-dimensional and two-dimensional fiber preforms, in the three-dimensional fiber preform, the fibers are densely and three-dimensionally woven, so that the fibers are in strong contact with each other and the fiber gap is narrow, resulting in The voids between them are not connected by a large flow passage as a whole. Therefore, the filling of the matrix material is so difficult.

In order to fill the matrix material into the dense fiber gaps as described above, it is necessary to infiltrate the matrix material or its precursor material (a material that becomes a matrix by a chemical reaction or thermal decomposition) at high pressure. . However, not only is there a limit to the increase in pressure, but in the firing process after the fluid matrix material is pressed in, the organic binder or precursor material undergoes thermal decomposition and the volatile components are released, so that FIG. As shown in (1), a large amount of pores 4 are generated in the matrix portion 3 between the three-dimensional fiber preforms 2 in the composite material 1. Therefore, in order to manufacture a densified composite material, the content of the pores should be reduced as much as possible.

[0005]

The technical problem to be solved by the present invention is to fill a gap in a three-dimensional fiber preform with a matrix material by densely pressurizing a slurry matrix material or a precursor material thereof and firing the matrix material. It is an object of the present invention to provide a method for producing a three-dimensional fiber-reinforced ceramic matrix composite material and a device therefor, which can reduce the content of pores later as much as possible.

[0006]

The composite material manufacturing method of the present invention for solving the above problems is a ceramic fine powder (this is called filler powder) as a matrix in a gap in a three-dimensional fiber preform. .) And an organic binder or a precursor substance thereof are densely packed,
A method for producing a three-dimensional fiber-reinforced ceramic matrix composite material, which comprises pressing a slurry containing the above filler powder and an organic binder or a precursor substance into the three-dimensional fiber preform at high pressure, Vacuum suction is performed from the opposite side of the three-dimensional fiber preform through a paper filter and a porous sintered metal plate, while suppressing passage of filler powder in the slurry and an organic binder or precursor substance as a solute in the paper filter. The ceramic-based composite material is characterized in that only the solvent portion is allowed to pass therethrough and discharged, and the three-dimensional fiber preform is highly densely impregnated with the slurry to obtain a ceramic-based composite material.

Further, the composite material manufacturing apparatus of the present invention uses a matrix as a matrix in the gap in the three-dimensional fiber preform.
A device for manufacturing a three-dimensional fiber-reinforced ceramic matrix composite material by densely filling a slurry containing a filler powder and an organic binder or a precursor substance thereof, which is provided in a cylinder pressurized by a piston. A space for accommodating the three-dimensional fiber preform and the slurry is provided, and the space is communicated with a suction chamber connected to a vacuum pump through a porous sintered metal plate and a paper filter laid on the periphery of the porous sintered metal plate. , The above paper filter,
The present invention is characterized in that the filler powder, the organic binder or the precursor substance in the slurry is suppressed from passing through, but the solvent portion is allowed to pass through.

More specifically, in the composite material manufacturing method of the present invention, a slurry formed by a filler powder, an organic binder and a medium liquid is used as a matrix substance, or a melt precursor substance, a melt precursor. A slurry of a liquid precursor substance comprising a body substance and a filler powder, a precursor substance dissolved in a solvent, or a precursor substance dissolved in a solvent and a filler powder is used.

As the above-mentioned filler powder, fine powders of various ceramics which serve as a matrix can be used. For example, when SiC is used as a matrix, β-SiC is used.
Fine powder (0.3 μm) is suitable. Polyvinyl alcohol and hydrocarbon wax are suitable as the organic binder. Melt precursor materials include polysilastyrene, polycarbosilane, polysilazane, polyhydrosilazane, and the like.

These slurries are pressed and impregnated at a high pressure into a fiber preform three-dimensionally woven with carbon fibers, glass fibers, and other appropriate reinforcing fibers to impregnate them.
Simultaneously with the press-fitting, vacuum suction is performed from the opposite side of the three-dimensional fiber preform through the paper filter and the porous sintered metal plate to suppress the passage of the filler powder, the organic binder or the precursor substance, and to actively the solvent portion. To discharge. The organic binder or precursor substance in the slurry undergoes thermal decomposition during the firing process during the production of the ceramic composite material, and the volatile components are released. This will be the case (Fig. 1). Reducing the content of organic binder or precursor material in the slurry and adding filler powder instead
This is effective for suppressing the generation of pores and producing a highly densified composite material.

One of the major roles of the organic binder and precursor material used in the present invention is to impregnate a slurry into a three-dimensional fiber preform and dry / fibre / fill in a green compact. It is to maintain the strength between substances to a certain degree and facilitate the subsequent work. For such purposes, the amount of organic binder or precursor material is
Empirically, 5-100% of the medium liquid is required. Further, the medium liquid needs to be 0.5 times or more the amount of the filler powder. As the matrix substance, it is particularly desirable that the content of the organic binder is 10% or less of the filler powder. Further, as the liquid precursor substance, the precursor substance is usually thermally decomposed into a ceramic in the firing process, and the ratio thereof is usually 70% or less.

[0012]

EXAMPLE FIG. 2 schematically shows a structural example of a composite material manufacturing apparatus of the present invention for filling the liquid matrix material as described above into the fiber gaps of a three-dimensional fiber preform. . This manufacturing apparatus is installed on a base 11 having a suction chamber 12 recessed therein, and on the upper part of the base 11.
A cylinder 13 having a cylinder hole 14 communicating with the suction chamber 12 is provided. The base 11 is configured such that an internal suction chamber 12 is connected to a vacuum pump through a suction passage 15 that opens at the inner bottom thereof, and an O-ring 17 is provided at a step in the suction chamber 12. Porous stainless bottom plate 1
6 is placed, a porous sintered metal plate (Poraston) 18 is mounted on the bottom plate 16, and the sintered metal plate 18
A paper filter 19 is laid on the top of the paper filter 19, and an O-ring 20 is interposed between the paper filter 19 and the cylinder 13 to prevent leakage of high-pressure slurry from the periphery of the paper filter 19.

The cylinder hole 1 in the cylinder 13
In the lower part of 4, a space for accommodating the three-dimensional fiber preform 5 and the slurry 6 is provided above the paper filter 19, and a piston 21 is fitted into the cylinder hole 14 through this space, The piston 21 is configured so that it can be pressed down by a ram 22 of a pressurizing device (not shown). Then, around the piston 21, an O-ring 23 and a necessary number of Teflon (trade name) piston rings 24 are mounted so that the slurry 6 does not flow backward from the gap between the piston 21 and the inner surface of the cylinder 13.

When the portion containing the three-dimensional fiber preform 5 and the slurry 6 is closed from above by such a piston 21, air is enclosed in the space above the slurry 6. In order to discharge this air, the piston 2
1 is provided with an air vent hole 26, and the hole 26 is provided at the inner end thereof.
A steel ball plug 27 for closing the above is inserted, and the steel ball plug 27 can be held in the closed position by a supply fixing screw 28 screwed into the air vent hole 26. The stainless steel bottom plate 16 has a large number of holes having a hole diameter of about 1 mmφ. Further, since the paper filter 19 blocks the passage of the filler powder (usually a particle size of 1 μm or less) in the slurry 6 and allows only the solvent portion to pass, the paper filter 19 has a thickness of 0.3 μm.
It has a hole diameter of about m.

By constructing the composite material manufacturing apparatus in this way, it is experimentally confirmed that the slurry 6 in the cylinder hole 14 does not exude to the outside even if the maximum pressure of 400 kgf / cm ² is applied to the piston 21. I'm sure. Further, in order to uniformly and densely fill the fine powder, the organic binder and the precursor substance in the slurry 6 into the fiber preform 5, the pressurizing speed in the pressurizing device is 0.05 to 50 mm / It can be set arbitrarily between min. Further, precision control of pressurizing speed (50 mm / min ± 0.2% for constant speed control, 1.00 to 20.00 tf for constant load control). Within ± 1%)
It is desirable to be able to.

When the three-dimensional fiber reinforced composite material is manufactured by the manufacturing apparatus having the above structure, first, the fiber preform 5 is put in the inner bottom of the cylinder hole 14, and the slurry 6, that is, the liquid matrix is placed on the fiber preform 5. The substance is put in a larger amount than the bulk volume of the fiber preform 5, and the piston 21
After loosening the steel ball fixing screw 28 in 1 to open the steel ball stopper 27 and discharging the air on the liquid surface of the slurry 6, the steel ball stopper 27 is closed again and the slurry 21 is pushed from above by the piston 21, and at the same time, downward. The slurry 6 is sucked into the fiber preform 5 by sucking the suction chamber 12 with a vacuum pump.
It is densely packed in the fiber gaps.

In this case, the O around the piston 21
Since the ring 23 and the required number of piston rings 24 are mounted, even if the piston 21 is pushed with high pressure, the cylinder 1
The slurry 6 does not flow back through the gap between the inner surface 3 and the inner surface 3. Further, at the bottom of the cylinder hole 14, O is provided at the upper part of the paper filter 19 and the lower part of the bottom plate 16, respectively.
Since the rings 20 and 17 are attached, the high-pressure slurry does not seep out to the outside, and the paper filter 19 blocks the passage of the filler powder in the slurry and passes only the solvent portion. This solvent portion is discharged into the suction chamber 12 through the holes in the porous sintered metal plate 18 and the bottom plate 16 below the paper filter 19.

The combined use of pressurization by the piston and suction by the vacuum pump in this manner has the following advantages. 1. When the fiber preform 5 and the slurry 6 are charged into the cylinder 13, and then the piston 21 is inserted to perform a pressurizing operation, the air remaining in the fiber preform 5 and between the upper surface of the slurry 6 and the piston 21 is , It can be easily sucked by the operation of the vacuum pump, and as a result, the matrix can be densely packed.

2. Slurry 6 charged before pressurizing operation
Is in a low viscosity state (the concentration of the organic binder or the precursor substance in the medium liquid is low) in order to facilitate the impregnation of the fiber preform 5 into the gap, but the pressurization by the apparatus of FIG. -Among the suction operations, particularly by the suction operation, a large amount of the solvent component in the slurry 6 can be desorbed, and as a result, the solute (organic binder or precursor substance) is in a high concentration state and the fibers are mixed with the filler powder. It becomes possible to fill the gap of the preform 5. It should be noted that this effect can be adjusted by the hole diameter of the paper filter 19 at the bottom of the cylinder 13 in FIG. Usually a small hole diameter (eg
With a paper filter of 0.3 or 0.1 μm) it is possible to leave a significant amount of solute fraction. 3. If the suction operation is used together with the pressurizing operation, the time required for desolvation in the slurry can be shortened.

Next, examples of the composite material manufacturing method of the present invention will be described. A three-dimensional fiber reinforced SiC composite material was produced using an apparatus having a configuration substantially as shown in FIG. As a three-dimensional fiber preform, a woven fabric (fiber content: 54%) in which carbon fibers are orthogonally organized into a flat plate having a thickness of 6 mm is used.
A piece cut into a size of 5 mm × 60 mm was used. on the other hand,
The slurry that is pressed into this three-dimensional fiber preform is 8
To 0 g of SiC fine powder (average particle size: 0.3 μm), 20 g of polysilastyrene was added as a precursor substance, and further,
It was prepared by adding 5 g of aluminum boride powder as a sintering aid to 100 g of toluene as an organic solvent and mixing them well.

A three-dimensional fiber preform woven from this slurry and carbon fiber was placed in a cylinder and pressurized to a maximum pressure of 24 MPa at a piston pressure rate of 0.05 mm / min for 1.5 hours. By holding, a fiber / ceramics precursor composite molded body was produced. Next, after subjecting this composite molded body to thermal decomposition of the precursor substance in Ar at 700 ° C.,
Further, by firing at 2000 ° C. in Ar for about 1 hour, a three-dimensional fiber reinforced / SiC composite material having a very small content of pores (porosity 15%) could be produced.

[0022]

According to the method and apparatus of the present invention, when the matrix material is filled in the gaps in the three-dimensional fiber preform, the slurry matrix material or its precursor material is densely pressed, It is possible to produce a three-dimensional fiber-reinforced ceramic matrix composite material having a high density by reducing the content of pores after firing as much as possible.

[Brief description of drawings]

FIG. 1 is an explanatory diagram for explaining a problem when a matrix material is filled between three-dimensional fiber preforms.

FIG. 2 is a side sectional view showing an embodiment of the composite material manufacturing apparatus according to the present invention.

[Explanation of symbols]

 5 fiber preform, 6 slurry, 13 cylinder, 18 porous sintered metal plate, 19 paper filter, 21 piston.

Claims (2)

[Claims] 1. A gap in a three-dimensional fiber preform is densely filled with a slurry containing a ceramic fine powder as a matrix and an organic binder or its precursor substance, and 3
A method for producing a three-dimensional fiber-reinforced ceramic matrix composite material, comprising: simultaneously pressing a slurry containing the ceramic fine powder and an organic binder or a precursor substance into the three-dimensional fiber preform at high pressure, Vacuum suction is performed from the opposite side of the three-dimensional fiber preform through a paper filter and a porous sintered metal plate, and while suppressing the passage of the ceramic fine powder in the slurry in this paper filter, only the solvent portion is passed and discharged. A method for producing a three-dimensional fiber-reinforced ceramic-based composite material, comprising obtaining a ceramic-based composite material in which a slurry is highly densely impregnated in a three-dimensional fiber preform. 2. A space in a three-dimensional fiber preform is densely filled with a slurry containing a ceramic fine powder as a matrix and an organic binder or its precursor substance, and 3
An apparatus for producing a three-dimensional fiber-reinforced ceramic matrix composite material, comprising: providing a space for accommodating a three-dimensional fiber preform and the slurry in a cylinder pressurized by a piston; The space is communicated with a suction chamber connected to a vacuum pump through a paper filter that is laid with its periphery sealed, and the paper filter suppresses passage of the ceramic fine powder in the slurry but allows the solvent portion to pass therethrough. An apparatus for producing a three-dimensional fiber-reinforced ceramic matrix composite material, which is characterized in that