JPH0516324B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for molding a fiber-reinforced composite ceramic molded article, and more specifically, to a method for molding a fiber-reinforced composite ceramic material, which is employed as a means to improve the toughness of the ceramic material. The present invention relates to a method for molding a fiber-reinforced composite ceramic molded body in which fibers can be blended in a desired arrangement with ceramic powder serving as a base material.

[Conventional technology]

Fiber-reinforced composite materials are composite materials in which the various properties of the base material are reinforced with fibers, and depending on the combination and blending ratio of the base material and the fiber material to be blended, high strength, high elasticity, low coefficient of thermal expansion, wear resistance, etc. can be achieved. Because it is possible to impart unique characteristics such as
It is attracting attention as a material for various industrial parts in the future.

As reinforcing fibers, boron, alumina,
Fibers such as silicon carbide are commonly used, and base materials include plastic materials,
Metal materials, ceramic materials, etc. are usually used.

Fiber-reinforced plastic (FPR) is made of plastic as the base material, fiber-reinforced metal (FRM) is made of metal as the base material, and fiber-reinforced ceramic (FRC) is made of ceramic as the base material. It is called.

By the way, among the various fiber-reinforced composite materials mentioned above, research and development is progressing on fiber-reinforced ceramic to improve the toughness of the ceramic base material, and the manufacturing method thereof is as follows. , A mechanical press molding method in which ceramic powder and fibers are placed alternately in a mold and then press molded.

A slip casting method in which fibers are placed in a plaster mold cavity and then a slurry-like slip, mainly made of ceramic material, is injected or sucked into the mold.

etc. have been adopted.

[Problem that the invention seeks to solve]

In view of the current state of the conventional technology as described above, the problem to be solved by the present invention is that in the conventional method for manufacturing fiber-reinforced ceramics, the mechanical press molding method that can be manufactured by this method is Fiber-reinforced ceramics are not only limited in shape to simple shapes such as test pieces, but also require a long time to mold, making them uneconomical.

In the slip casting method, the slip of ceramic material is not normally as low viscous as molten metal, and in order to achieve a low viscosity it is necessary to reduce the content of ceramic powder. Cracks tend to occur when drying ceramic molded bodies, and if the content of ceramic powder is increased to make it highly viscous, it is not only difficult for slips to sufficiently penetrate into the gaps between fibers, but also to cause slips to break. Due to the flow of the fibers, the fibers arranged in a predetermined arrangement state become entangled and aggregate, or the fibers move from the predetermined arrangement position, resulting in fiber reinforcement having the desired arrangement/arrangement state. It is difficult to form a ceramic molded body, and there is no reliable method for positioning the fibers within the cavity of the plaster mold.

etc.

Therefore, the technical problem of the present invention is to
A foamed resin molded body containing fibers that have been fixed in a predetermined arrangement state at both ends using the foaming property of a resin material that is fixed in a predetermined arrangement state is ceramic molded. A slurry-like slip of ceramic powder containing a solvent solution such as benzene that can cause extreme shrinkage or disappearance of foamed resin is placed inside a plaster mold cavity having the shape of a human body. By injecting it into the cavity, it is possible to mold a fiber-reinforced composite ceramic molded product in which fibers are blended in a predetermined arrangement state at a desired location when manufacturing a fiber-reinforced composite ceramic molded product. It's about doing.

[Means for solving problems]

In view of these problems with conventional technology,
The means for solving the problems of the conventional technology in the present invention includes a step of fixing both ends of the fibers arranged in a predetermined arrangement state using a fixing jig, and a step of fixing the ends of the fibers arranged in a predetermined arrangement state in a cavity of a mold having a predetermined shape. There is a step of arranging fibers with fixed ends at both ends, and a step of filling the cavity of this mold with a foamable resin material such as polystyrene, and then filling the cavity with foam to arrange the fibers in a predetermined arrangement. A process of fixing the foamed resin molded body with fibers fixed in a predetermined arrangement inside the molded body in a core shape inside a plaster mold cavity having the shape of the ceramic molded body to be molded. and slip casting, in which a slurry-like slip, which is a uniform mixture of a solvent solution such as benzene that can cause the foamed resin to shrink or disappear, a surfactant, and ceramic powder, is injected into the cavity of the plaster mold. and a step of degreasing and drying the ceramic molded body cast by the above-mentioned slip casting process, the method comprising the steps of:
A solvent solution injected into the cavity of the plaster mold causes the foamed resin to shrink or disappear, and is filled with ceramic powder instead of the foamed resin.
The method consists of forming a fiber-reinforced composite ceramic molded body, which is characterized by forming a ceramic molded body containing fibers in a cavity in a plaster mold.

[Effect]

Hereinafter, the effects of the present invention will be explained.

In the present invention, the means for solving the problems of the conventional technology is configured as described above, and a foamed resin containing fibers whose arrangement state is fixed by foamed resin in a plaster mold cavity is provided. The molded body is placed in a core state, and a slurry-like slip is formed by uniformly mixing a solvent solution that can cause the foamed resin to shrink or disappear, a surfactant, and a ceramic powder. Therefore, when producing a fiber-reinforced composite ceramic molded product, it is possible to mold a fiber-reinforced composite ceramic molded product in which fibers are blended in a predetermined arrangement state at a desired location. .

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the accompanying drawings.

FIGS. 1 to 7 are diagrams showing each step of the method for forming a fiber-reinforced composite ceramic molded article according to the method of the present invention.

Hereinafter, the method for molding a fiber-reinforced composite ceramic molded article of the present invention will be explained along with its steps.

In addition, as the fiber 2 used in the method of the present invention, SiC
Various fibers 2 such as long fibers, carbon fibers, metal fibers such as boron fibers, glass fibers, oxide fibers such as alumina fibers, zirconia fibers, etc. can be suitably used.

FIG. 1 shows a situation in which fibers 2 to be mixed into a fiber-reinforced composite ceramic molded body are fixed to a fixing jig 1.

In this first step, first, using arbitrary fibers 2 from among the above-mentioned various fibers 2, the alignment direction of the fibers 2 is aligned, and both ends of the bundle of fibers 2 are fixed with the fixing jig 1. Secure as shown.

The fixing jig 1 is preferably made of wax that has a low melting point and high strength at room temperature, but it may also be made of a resin that is easily removed by thermal melting or thermal decomposition.

Further, it is desirable that the shape of the fixing jig 1 be determined in advance in consideration of its positioning in the mold in the next second step of fixing the fibers 2 with expanded polystyrene.

FIG. 2 shows a situation where the arrangement of the fibers 2 is fixed by expanded polystyrene.

In this second step, the fixed body of the fiber 2 whose both ends were fixed by the fixing jig 1 as described above was placed in a test mold 5 with a cavity volume of 180 mm width x 15 mm thickness x 250 mm height. The raw material particles of polystyrene are filled into the mold 5 by pneumatic transport from the filling port 4, and the foaming rate is increased to about 30 times by the usual method to form fibers 2 in the expanded polystyrene.
This is the process of fixing.

Note that the foaming rate of the expanded polystyrene is preferably 15 to 60 times; if it exceeds 60 times, the expanded polystyrene will be easily deformed, and if it is less than 15 times, the residue of the expanded polystyrene will remain in the ceramic molded body 9 in the subsequent fourth step. This is not preferable because it becomes easy to form cavities in the ceramic powder molded body 9.

FIG. 3 shows a foamed polystyrene molded product 6 which is removed from the mold after foaming polystyrene within the cavity of the mold 5 and fixing the fibers 2 therein in a desired arrangement.

The foamed polystyrene molded body 6 demolded from the mold cavity of the mold 5 in this third step has a main body formed of foamed polystyrene, and the inside thereof has fibers placed inside the mold cavity in the second step shown in FIG. 2 are fixed in the arrayed state arranged in the first step.

FIG. 4 shows a state in which the expanded polystyrene molded body 6 demolded in the third step is installed in the cavity of a plaster mold 7 in the form of a core.

In this fourth step, the foamed polystyrene molded body 6 is molded into a plaster mold 7 in the shape of the ceramic molded body 9.
It is installed like a core inside the cavity.

Note that the fixing jig 1 also functions as a positioning jig for mounting the plaster mold 7 into the cavity in this step.

Further, 8 is a slip injection port through which slip is injected for slip casting.

Various types of slips can be used, and examples of five types of slip compositions are shown below.

In addition, all the contents shown below are displayed by weight%.

A: Ultra fine grade SiC; 76% polycarboxylic acid peptizer; 1.5%, polyacrylic binder; 1.0%, benzene; 21.5%, B: Si ₃ N ₄ powder; 80.5%, polycarboxylic acid peptizer Peptizer; 0.6%, toluene; 18.9%, C: Si ₃ N ₄ powder; 79.0%, water glass peptizer; 0.4%, distilled water; 20.6%, D: borosilicate glass powder; 73.5%, ( Average particle size 1.5μ) Polyoxyalkyl phosphate peptizer; 0.8
%, polyacrylic binder; 1.2%, trichlorethylene; 24.5%, E: carbonyl Ni powder; 78.6%, (average particle size 3.8μ) polycarboxylic acid peptizer; 0.5%, benzene; 20.9%, etc. be.

Among the five types of slip compositions mentioned above, A, B, and D
The solvent liquid used in and E is an organic solvent such as benzene, toluene, or trichlorethylene, and since these organic solvents can cause the foamed polystyrene to shrink or disappear extremely, they are replaced with the foamed polystyrene. As a result, the liquid level of the slip containing ceramic powder rises from below in FIG. 4, and is replaced by a ceramic molded body 9 having fibers 2 blended therein.

In addition, since slip C uses distilled water as the solvent, the expanded polystyrene cannot be removed as it is.

Therefore, when using slip C, an organic solvent such as benzene is mixed in the slip using distilled water as a solvent, and then the solvent is injected into the plaster mold cavity. It is necessary to first shrink or eliminate the expanded polystyrene using an organic solvent such as benzene, and then fill the plaster mold cavity with the slip.

In addition, when slip casting,
It is preferable to apply pressure of 0.2 to 2 atmospheres with air to ensure that the slip is filled.

FIG. 5 shows a ceramic molded body 9 which was removed from the mold after a slip was injected into the cavity of the plaster mold 7 and the foamed polystyrene inside was replaced by the slip.

In this fifth step, after installing the core-shaped foamed polystyrene molded body 6 in the plaster mold 7, slip is injected to replace the foamed polystyrene with the slip.
This is a step of demolding the ceramic molded body 9 after the inking time has elapsed.

The appearance of the demolded ceramic molded body 9 is the same as that of the completed ceramic molded body 9.

FIG. 6 shows a situation in which the fixing jigs 1 fixed to both ends of the ceramic molded body 9 are removed by heating and melting them with the fixing jigs 1 facing downward.

This sixth step is a step in which the fixing jigs 1 fixed to both ends of the ceramic molded body 9 are removed by heating and melting them with the fixing jigs 1 facing downward.

Note that this step causes the fixed end of the fiber 2 to become the sixth
It appears as shown in the figure.

Figure 7 shows the fixing jig 1 at both ends in the sixth step.
The ceramic molded body 9 is shown in a completed state after being removed by heating and melting.

In this seventh step, the fixtures 1 fixed to both ends of the fibers 2 are removed by heating and melting, left in dry air for 6 hours, and then left at 45° C. for 8 hours.

Note that heating up to 450° C. is performed as a degreasing treatment to remove the organic binder, if necessary.

In the ceramic molded bodies 9 molded according to the method of the present invention as described above, good ceramic molded bodies 9 with no "cracks" were obtained in all cases, and cross-sectional observation of the fractured ceramic molded bodies 9 It was confirmed that the fibers 2 were present in the ceramic molded body 9 in the same arrangement as in the first step.

〔Effect of the invention〕

As is clear from the above, according to the method for molding a fiber-reinforced composite ceramic molded article according to the present invention, fibers fixed at both ends are arranged in a predetermined state in advance by utilizing the foamability of a resin material having foamability. Then, a foamed resin molded product containing fibers fixed in a predetermined arrangement state is installed in a core shape in a plaster mold cavity having the shape of a ceramic molded product, and a foamed resin such as benzene is By injecting a slurry slip of ceramic powder containing a solvent solution that can cause extreme shrinkage or disappearance into the cavity of a plaster mold, it is possible to form a fiber-reinforced composite ceramic molded article at a desired location. This method has the advantage that it is possible to mold a fiber-reinforced composite ceramic molded article in which fibers are blended in a predetermined arrangement state.

[Brief explanation of drawings]

Figure 1 shows a situation in which fibers are fixed in a desired arrangement using a fixing jig, and Figure 2 shows a fixing body in which fibers are fixed in a desired arrangement to a fixing jig, and is attached to a mold. Figure 3 shows the situation in which
Figure 4 shows a molded product of foamed polystyrene that has been removed from the mold after being formed by filling the cavity of a mold with foamed polystyrene. Figure 5 shows a ceramic molded body formed by a plaster mold, and Figure 6 shows how it is being installed.
FIG. 7 is a diagram showing a situation in which a fixing jig is melted and disappeared from a ceramic molded body. FIG. 7 is a diagram showing a ceramic molded body in which a fixing jig is melted and disappeared. 1... Fixing jig, 2... Fiber, 3... Cavity, 4... Foaming agent filling port, 5... Mold, 6...
Expanded polystyrene molded body, 7... Plaster mold, 8...
Slip injection port, 9...ceramic molded body.

Claims (1)

[Claims] 1. A step of fixing both ends of the fibers arranged in a predetermined arrangement using a fixing jig, and placing the fixed fibers at both ends in a cavity of a mold having a predetermined shape. A step of filling the cavity of this mold with a foamable resin material, and then filling the cavity with foam to fix the fibers in a predetermined arrangement state; A step in which the foamed resin molded bodies fixed in an arrayed state are installed in a core-like manner in a plaster mold cavity having the shape of the ceramic molded body to be molded, and a solvent capable of causing extreme shrinkage or disappearance of the foamed resin. A liquid agent, a surfactant, and a ceramic powder,
It consists of a slip casting process in which a homogeneously mixed slurry slip is injected into the cavity of the plaster mold, and a process in which the ceramic molded body cast by the slip casting process described above is degreased and dried. A method for forming a fiber-reinforced composite ceramic molded article, which comprises:
A solvent solution injected into the cavity of the plaster mold causes the foamed resin to shrink or disappear, and is filled with ceramic powder instead of the foamed resin.
A method for molding a fiber-reinforced composite ceramic molded body, which comprises forming a ceramic molded body containing fibers in a cavity in a plaster mold.