JPH04104967A - Production of fiber-reinforced composite ceramic material having 2d fiber texture formed by lamination of impregnated woven fabric prepreg - Google Patents

Abstract

PURPOSE:To remarkably improve the fracture toughness and breaking energy of a fiber-reinforced composite ceramic material by passing a continuous woven fabric sheet through an impregnation liquid containing a specific preceramic polymer and ceramic powder and heating the resultant prepreg laminate under specific condition. CONSTITUTION:The subject production process is composed of (1) a process for producing an impregnation liquid by adding one or more kind of powdery ceramics selected from mullite, alumina and silicon nitride to a solution composed of an inorganic material or a preceramic polymer containing silicon and nitrogen as essential components and having a total carbon number of >=7 in the main recurring unit, (2) a process for producing a prepreg laminate having two-dimensionally oriented fiber structure by passing a continuous woven fabric sheet through the impregnation liquid and (3) a process for the primary heat-treatment of the prepreg laminate in an inert gas or nitrogen gas atmosphere at 400-700 deg.C and the secondary heat-treatment of the product in the above atmosphere at 1500-1800 deg.C under normal or positive pressure.

Description

[Detailed Description of the Invention] [Technical Field to which the Invention Pertains] Ceramics are attracting attention as structural materials, and their application to high-temperature structural materials as heat-resistant materials is being actively promoted. However, in monolithic ceramics (single sintered bodies), the bending strength has improved to the extent equivalent to that of metal materials, or the fracture toughness value (K, c) or the fracture work (
r) etc. are far inferior to νOr, so there is an urgent need to improve both.

The idea of reinforcing the matrix phase with the fiber phase is PRM (
Fiber Reinforced Metal),
FRP (FiberRejnf'orced Pla
stics), etc. Especially in recent years, fibers (carbon fibers) have excellent properties.

Boron fibers, silicon carbide fibers, silicon nitride fibers, tyranno fibers, glass fibers, etc.) have been developed, and their application to fiber-reinforced ceramic composites is being studied.

The present invention is based on the above idea.

A fiber-reinforced ceramic composite material is created by creating a prepreg using ceramic as a matrix phase using the sheet winding (S/W) molding method and solution impregnation method, and then laminating the sheets so that the fibers are oriented in a desired manner. It concerns the manufacturing method.

[Prior Art and Problems] Ceramic materials have excellent mechanical properties such as heat resistance, reaction resistance, and wear resistance. As is well known, it is applied to sub-combustion chambers for diesel engines, turbochargers, etc. as an engine supplement, and it is expected that it will also be applied to gas turbine engines in the near future.

However, even compared to aluminum alloy, which is considered to be relatively brittle among metals, ceramic has a low fracture toughness value, which is why it is said to be a brittle material. In such monolithic ceramics, it is impossible to dramatically improve the fracture toughness even if nine-structure control is performed, and there is a strong demand for fiber-reinforced composite materials.

Applications regarding fiber-reinforced ceramic composites include spinel (MgO・Al!zOa) and silicon carbide.

Sintered body mixed with short fibers (JP-A-62-119175)
.

A sintered body made of alumina mixed with silicon carbide and short fibers (Unexamined Japanese Patent Publication No. 6)
2-119174), carbon continuous fiber reinforced SIC composite (Japanese Patent Laid-Open No. 61-247H3), ceramic composite material in which carbon fibers are added to metal oxides or carbides and sintered at the same time as pressure is applied (Japanese Patent Laid-open No. -13HO6), silicon carbide, fiber-reinforced ceramic composite (Special Publication No. 623599
B), and fiber-reinforced sialon composite material (JP-A-1-1
31074), Fiber-reinforced ceramic composite material reinforced by particle dispersion and its manufacturing method (JP-A-2-2 [1g7B
, 2-28877), Fiber-reinforced mullite composite material reinforced by particle dispersion and method for producing the same (JP-A-2-1838)
4) etc. However, for composite materials using long fibers to which the present invention belongs, -dimensionally oriented fiber structure (rlDID hereinafter)
(also referred to as fibrous structure), and composite materials with this ID fibrous structure have low interlaminar shear strength (for example, JP-A-2-2887
6, JP-A-2-2-26877 and JP-A-2-18364, the composite material has a principal stress of about 115 to 1110), and of course, it is a material that has a remarkable directionality in terms of work of fracture.

Therefore.

When such a composite material is used in applications where complex stress is generated, the work of fracture in the direction perpendicular to the direction of fiber elongation is extremely low, causing peeling or fracture due to shear between the two layers.

[Means for Solving the Problems] Therefore, in the present invention, long fibers are uniformly dispersed in ceramics as a matrix phase, and by utilizing thermal decomposition of a preceramic polymer, especially an inorganic polysilazane, containing silicon and nitrogen as essential components, and two-dimensionally oriented. By molding it as a prepreg laminate having a fiber structure (hereinafter also referred to as "r2D fiber structure"), we aim to dramatically improve the fracture toughness value or work of fracture of the fiber-reinforced ceramic composite material.

This makes it possible to use it even in applications where particularly complex stress is generated. That is, the above problem was solved by the following solution.

(1) One or more ceramic powders selected from the group consisting of mullite, alumina, and silicon nitride are added to a solution consisting of a preceramic polymer containing silicon and nitrogen as essential components and having an inorganic material or a total number of carbon atoms in the main repeating unit of 7 or less. The process of adjusting the blended impregnating liquid.

A step of passing a woven continuous sheet of fibers through an impregnating liquid to obtain a prepreg laminate having a two-dimensionally oriented fiber structure, and a primary heat treatment of the prepreg laminate at 400 to 700°C in an inert gas or nitrogen gas atmosphere. , followed by a step of secondary heat treatment in the same atmosphere at 1500 to 1800°C under normal pressure or pressure.

A method for producing a fiber-reinforced ceramic composite material, characterized by comprising:

(2) One or more ceramic powders selected from the group consisting of mullite, alumina, and silicon nitride are added to a solution consisting of a preceramic polymer containing silicon and nitrogen as essential components and having an inorganic material or a total number of carbon atoms in the main repeating unit of 7 or less. The process of adjusting the blended impregnating liquid.

A step of immersing a textile unit sheet of fibers in an impregnating liquid to obtain a prepreg sheet having a two-dimensionally oriented fiber structure.

A process of sequentially stacking prepreg sheets with the orientation directions of their fibers crossing each other to form a prepreg laminate of an arbitrary shape, and a primary heat treatment of the prepreg laminate at 400 to 700°C in an inert gas or nitrogen gas atmosphere. , followed by a step of secondary heat treatment in the same atmosphere at 1500 to 1800°C under normal pressure or pressure.

A method for producing a fiber-reinforced ceramic composite material, characterized by comprising:

Here, as the preceramic polymer, perhydropolysilazane with main repeating unit -+5iHzNH+-, main repeating unit -+5i-NHk (R is an alkyl group, alkenyl group, aryl group, cycloalkyl group, alkyl group having 7 or less carbon atoms) Polysilazane (representing a silyl group, alkylamino group or alkoxy group), and carbon fibers are most suitable as the fibers.

In order to significantly improve the fracture toughness value or the work of fracture, which is the objective of the present invention, it is important to know how to uniformly distribute the two dispersed phases in the matrix phase, how to generate stress at the fiber-matrix interface, and how to fracture the fiber-matrix interface. What is important is how the fibers are pulled out.

Regarding the generation of interfacial stress, σ: Stress generated in the parallel direction of the woven fibers Δα: Difference in thermal expansion coefficient between the matrix and fibers ΔT: Difference between sintering temperature and operating temperature S: Poisson's ratio a: Fiber radius r: From the center of the fiber Distance Em: The generation of stress expressed by the Young's modulus of the matrix induces non-uniformity in the direction of crack propagation (crack deflection), which increases with the work of fracture.

Regarding the fiber-matrix interface work, W: Work done by the fiber on the matrix d: Fiber diameter i: Fiber length Δ Oni pull-out distance σ: Due to the energy dissipated at the interface during pull-out due to the stress acting on the fiber cross section. Destructive work increases.

Regarding improvement of fracture toughness value.

K −-” and (K )2+VrrR2Ec
・-■IC-c Em IC-mK
: Fracture toughness value of composite material IC-c K : Fracture toughness value of matrix IC Kenrin EC: Elastic modulus of composite material Em: Elastic modulus of matrix V: Volume fraction of fiber τ: Fiber-matrix interface strength r : Woven fiber radius R: The fracture toughness value improves comprehensively (linear region and non-linear region) depending on the aspect ratio of the drawn fibers.

By (1) and (2), the fracture work of the composite improves comprehensively (in the linear region and nonlinear region), and metastable or stable fracture occurs. A particularly important point is that composite materials are nonlinear materials, and the nonlinear displacement range other than the two elastic deformations is very important.

Equations (1) and (2) indicate the importance of controlling the stress (strength) acting on the interface.2 According to the present invention, the interfacial stress can be effectively controlled, and the fracture toughness value or work of fracture can be significantly improved. We were able to resolve this direction. In this case, the products of thermal decomposition of certain Brecerami-Sox polymers, especially inorganic polysilazane, may perform important functions such as forming an intermediate layer useful for toughening at the interface between the fiber and the ceramic matrix, or toughening the ceramic matrix itself. It is thought that it is fulfilling its role.

especially.

When mullite or alumina is used as a ceramic powder as a raw material, the silicon nitride produced by thermal decomposition of a preceramic polymer containing silicon and nitrogen as essential components further reacts with the mullite or alumina, and the matrix is completely or partially Generates Sialon.

This also shows that the fiber-reinforced ceramic obtained by the present invention
This is because the composite material significantly increases the fracture toughness value.

It is also assumed that the reaction and sintering are sufficiently progressed due to the formation of sialon, and this is also considered to contribute to the improvement of high strength and toughness.

In addition, when silicon nitride is used as the ceramic powder,
Since the matrix itself is stronger, in combination with interfacial stress control through thermal decomposition of inorganic polysilazane, it is possible to provide a fiber-reinforced ceramic composite material that is even stronger.

In addition, other physical properties such as bending strength and abrasion resistance.

There is a fundamental difference between the material mechanical index such as surface hardness 1 and the fracture toughness value and work of fracture exhibited by the composite material according to the present invention. That is, in terms of these other physical properties, high strength, high hardness, and high wear resistance can be achieved if sintering is completed and pores are reduced. However, in composite materials such as those according to the present invention, the stress in the direction parallel to the fibers, the interfacial work between the fibers and the matrix, and the fracture toughness values expressed by the formulas It is necessary to control the

Alumina and mullite can react with silicon nitride synthesized from preceramic polymers to synthesize sialon. As a heat-resistant structural material, β-sialon (Sis-2Aj!z Ol Ns-zz-1,2,3
, 4 or even less than 1) is valid. However, in addition to this β-sialon, the sialon phase obtained in the present invention can synthesize a crystalline phase at a low temperature, so that a low-temperature type sialon (Si]2A121s Owe Ns) is produced, which is very effective.

In addition, in order to form a matrix of only silicon nitride phase without reacting with silicon nitride synthesized from the preceramic polymer, silicon nitride, which is strong itself, may be used as the ceramic raw material powder, and fibers produced by thermal decomposition of the preceramic polymer may be used. Sufficient toughness can be achieved by controlling the interface between the steel and the matrix. Therefore, in this case, it is not necessary to use alumina, mullite, etc. It goes without saying that these ceramic powders may be mixed and used, and other ceramic powders such as aluminum nitride, silica, etc. may be added to the powder as long as it does not adversely affect the toughness.
There is no problem even if they are used together in an amount of owt% or less.

Preceramic polymers, particularly inorganic polysilazane, include perhydropolysilazane having a molecular weight in the range of about 100 to 50,000 in which the predominant repeating unit is expressed as 1+5iH2N)l+-. This perhydropolysilazane is 1 depending on the degree of polymerization.

It can be obtained as an oil or powder. In either case, it is easily soluble in a solvent such as xylene. Therefore, by adding alumina powder or the like and inorganic polysilazane to such a solvent and mixing them, it is possible to easily and uniformly distribute the alumina powder and the like. Here, since the inorganic polysilazane also acts as a deflocculating agent (dispersing agent), the two-tube slurry becomes a homogeneous slurry suitable for granulation or slurry molding. When the prepreg obtained from the fibers impregnated with this slurry is heat-treated, the inorganic polysilazane is thermally decomposed, hydrogen is volatilized, highly active Sl and N act as binders, and the particles are strongly bound together. , ceramic particles are alumina,
In the case of mullite, these and highly active 81. N reacts with each other to generate sialon. Here, this bonding force is stronger as a preceramic polymer with a higher pyrolysis yield is used, and a preceramic polymer that does not leave excess carbon that does not participate in bonding,
Furthermore, the presence of organic groups makes it difficult to form sialons. Therefore, inorganic polysilazane, which essentially has no organic groups and has a highly pure 5i3N4 composition after pyrolysis, can be said to be a suitable preceramic polymer. Also, the forms of Si and N (as intermediate substances) after this thermal decomposition are as follows.

Usually, it fills the spaces between ceramic particles in the form of amorphous particles or extremely small crystal particles of 1000 Å or less, and is also highly reactive with alumina particles and the like.

The above reaction starts at about 400°C and is completed at about 1500°C. According to the present invention, since the secondary heat treatment is performed at about 1500 to 1800° C., sialon is generated, sintering progresses, and a shaped sintered body of sialon ceramics having excellent mechanical properties such as toughness can be obtained.

Further, the amount of the inorganic polysilazane added can be increased or decreased without restriction depending on the properties of the target composite material, such as strength, density, workability, etc.

This is because, unlike conventional preceramic polymers, by increasing the degree of polymerization, the degree of melting can be reduced and softening of the molded body can be prevented even when a large amount is added. However.

In order to maximize the contribution to the primary forming aid and matrix reaction, the amount of ceramic powder used should be 85 to 50v.
of% preferably needs to be about 75vof%.

The inorganic polysilazane used in the present invention is a polysilazane that essentially does not have an organic group in its side chain, and preferably has a molecular weight (degree of polymerization) of about 100 to 50,0 f)0 (about 2 to 10
It is a polysilazane within the range of 00).

Such an inorganic polysilazane can be produced by, for example, reacting a dihalosilane with a base to produce a dihalosilane adduct, and then reacting this adduct with ammonia (see JP-A-60-145903).
.

If the molecular weight of the inorganic polysilazane used in the present invention is less than 100, it will evaporate together with the solvent, and its effectiveness as a binder will tend to be weakened. If it is greater than 50,000, it will not be needed as a solvent, resulting in non-uniform mixing, resulting in poor ceramic composite materials. strength tends to decrease.

To mold ceramics using such inorganic polysilazane, as described above, ceramic powder and inorganic polysilazane are added and mixed in a solvent to create a slurry, and the slurry is molded.

Examples of solvents include hydrocarbon solvents such as aliphatic hydrocarbons, alicyclic hydrocarbons, and aromatic hydrocarbons, halogenated hydrocarbons such as halogenated methane, halogenated ethane, and halogenated benzene, aliphatic ethers, and alicyclic ethers. Ethers such as can be used.

Preferred solvents are methylene chloride and chloroform.

Halogenated hydrocarbons such as carbon tetrachloride, bromoform, ethylene chloride, ethylidene chloride, trichloroethane, tetrachloroethane, and ethyl ether.

Isopropyl ether, ethyl butyl ether.

Ethers such as butyl ether, 1,2-dioxyethane, dioxane, dimethyldioxane, tetrahydrofuran, tetrahydropyran, pentane, hexane, isohexane, methylpentane.

Heptane, isohbutane, octane, isooctane, cyclopentane, methylcyclopentane.

These include hydrocarbons such as cyclohexane, methylcyclohexane, benzene, toluene, xylene, and ethylbenzene.

In addition to inorganic polysilazane (perhydropolysilazane), other preceramic polymers that can be thermally converted into sialon by reaction with mullite and/or alumina include polysilazane and polyorganohydrosilazane as organic polysilazane.

Among these, as polysilazane, JP-A-60-228
The main repeating unit disclosed in 890 is -fS1-NH
Examples include +- (R is an alkyl group having 7 or less carbon atoms, etc.). Examples of polyorganohydrosilazane include those produced by reacting dry ammonia with a complex of a polyorganohydrodihalosilane and a Lewis salt (Japanese Patent Application Laid-open No. 89230/1983, No. 62).
-156135. U.S. Pat. No. 4,859.1i50). Also, polymetallosilazanes, which are reaction products of polysilazane and metal alkoxides (the metal is aluminum, yttrium, etc.) (for example, JP-A-63-191832.
83-88221) can be used as long as it can be thermally converted into Sialon.

However, no matter which organic polysilazane is used, the total number of carbon atoms in rRJ is 7 or less, more preferably 1 carbon atom.
~2 alkyl groups, etc. This is because as the total number of carbon atoms increases, free carbon is generated and the conversion rate to ceramics (particularly silicon nitride) becomes extremely low.

Furthermore, in the production of the composite material of the present invention, perhydropolysilazane (inorganic polysilazane) is preferable to these organic polysilazane. Due to the presence of rRJ, some carbon (C) atoms remain after thermal decomposition, and moreover, the carbon exists in an amorphous state. Therefore, densification is hindered, such as the generation of pores due to decarburization. In particular, the relationship between 1 strength and toughness has no significant effect at room temperature, but at high temperature (5
(00-800°C or higher), the presence of amorphous C atoms may cause a decrease in strength and toughness.

Note that other silicon-containing polymers 1 such as siloxazane, polysilastyrene, and polycarbosilane are not preferred. This is because, although siloxasan has the possibility of producing sialon, it has an inferior binder effect, and polysilastyrene and polycarbosilane mainly produce silicon carbide through thermal decomposition. However, even these silicon-containing polymers can be used if they are modified in some way, such as by introducing nitrogen atoms into their skeletons.

The preceramic polymer has the dual role of being a primary forming aid and contributing to matrix reactions. Due to its role as an auxiliary agent or various behaviors in the matrix forming process, the amount of ceramic powder used is 85vo1% to 50% based on the total amount of preceramic polymer and ceramic powder.
voffi%, preferably about 75voR% (when converting a preceramic polymer into silicon nitride).

As an example, when a ceramic powder of about 75 voffi% is used, the crystalline phase generated by the reaction of silicon nitride from a preceramic polymer will be considered using actual measurement data (identified by X-ray diffraction).

(1) In the case of alumina, the crystal phase produced is Sil□A171
g0HN, and V2O,.

(2) In the case of mullite, the crystal phase formed is 8112 Aj!
1s OasNll and 3 AI! 20g ” 28
102°Also, SIO□ of mullite becomes silicon nitride in a +N2 atmosphere and contributes to a similar reaction.

That is, since both systems contain a large amount of ceramic powder, an unreacted ceramic phase (AJ' 20 s
or 3Ai1203・2s1o2), low-temperature sialon (S11
2Al! It can be qualitatively confirmed that +sOs@Ns) phase is generated.

In addition, the average crystal grain size of the matrix varies depending on the radius of the fibers2. For example, when 8 fibers are used, it is preferably 6 ua or less (more preferably 31 ua or less), and 1
When using 0 fibers, preferably 7.5- or less (
more preferably 3.58 or less). Further, it is desirable that the open porosity is 5% or less.

It is used to react silicon nitride with alumina or mullite to form sialon. Alternatively, it is desirable that the individual ceramic powders produced be as fine as possible. For this reason, alumina or mullite was used as a raw material of 1- or less, and silicon nitride was synthesized using a thermal reaction from a preceramic polymer. Therefore, the preceramic polymer is dissolved in a solvent (toluene, xylene, etc.) and the ceramic powder, which will become the other matrix component, is dispersed therein.
This is an impregnating liquid used in winding molding method (S/W molding method) or sheet lamination method.

For fiber reinforcement, the long fibers used are carbon fibers (bread-based, pitch-based), carbon fibers coated with ceramic thin films such as alumina and silicon carbide to improve oxidation resistance (bread-based, pitch-based), and tungsten. Carbon fiber (bread-based, pitch-based) plated with heat-resistant metals such as those typified by ultra-heat-resistant metal fibers such as tungsten, molybdenum, and tantalum 1 whose surface is treated with boron, silicon carbide, and boron carbide tungsten fibers, as well as ceramic fibers such as alumina fibers, silicon carbide fibers, silicon nitride fibers, and tyranno fibers. Carbon fiber is particularly preferred because of its reaction with the matrix and its heat resistance. The amount of fibers dispersed in the matrix can be adjusted by the viscosity of the impregnating liquid and the fiber passage speed, but it is most preferably about 35 to 60% by volume relative to the matrix.

These long fibers are pre-woven (hand-woven, bias-woven,
It is a continuous sheet of satin weave) or a unit sheet of woven fabric.

A sheet winding method (S/W method) or a sheet dipping method was employed to uniformly distribute the fibers or their fabrics in the matrix.

That is, in the case of the S-molding method, the supplied continuous woven sheet of long fibers is basically a strand that has been changed into a woven sheet, and this sheet is continuously passed through the impregnating liquid and mechanically wound. By removing the fibers, a prepreg having a two-dimensionally oriented fiber structure is created (FIG. 2). In Figure 2, 10 is a spool, +2 is a (long) fiber woven fabric, 14
is the impregnation liquid tank.

1B is an impregnating liquid, 18 is a winding drum, and 20 is a roller. In addition, in the case of the sheet dipping method, unit sheets 12 of the fabric are immersed one by one in the impregnating liquid to create a prepreg sheet having a two-dimensionally oriented fiber structure, and this prepreg sheet is adjusted to have a cross angle or a phase angle (0) of the fibers. A prepreg laminate of an arbitrary shape is created by sequentially laminating the layers at θ≦90＠, preferably 25≦θ≦90”, more preferably 25≦θ≦75° (Fig. 3,
Figure 4).

In the case of the S/W molding method, the continuous woven fabric sheet may be passed through an impregnating liquid until the prepreg reaches a predetermined thickness.

The obtained prepreg (laminate) is pressure-molded using a biaxial pressure press or a cold or hot isostatic press (CIP or VIP), and then the solvent is completely removed in an oven. and nitrogen gas or argon gas.

Alternatively, the preceramic polymer is thermally decomposed (400 to 700°C) in a nitrogen gas and ammonia mixed gas stream. At this time, the preceramic polymer becomes insoluble and infusible and becomes an amorphous material having a silicon nitride composition.

When sintering, sintering may be carried out under argon gas or nitrogen gas pressure (~9.8 cg/cd) or under normal pressure gas (airflow) at a temperature of 1500 to 1800 °C, more preferably 1700 °C or less. Also, since sintering of the matrix becomes difficult to proceed due to filling with fibers, after masking the surface of the molded product with boron nitride,
Place carbon or other heat-resistant material into the mold and hot press (for example ~
It is also preferable to carry out sintering (350 kg/cd).

The evaluation methods used to compare the properties of composite materials are: ■ Qualitative identification of the crystalline phase of the matrix by X-ray diffraction ■ Fracture toughness value by 5ENB method (sample 5 mm x g am x 80+u.

a/w -0,5) Work of fracture by SENB method test piece rwof 2S S: Fracture area E: Fracture energy from load-displacement curve ■ Bending strength (sample 3×4 mm×4 hm), etc.

[Example] (Example-1) First, create an impregnating solution for creating a matrix.

Mn-1818, My-8347,81/N-1
, 22 perhydropolysilazane solution (manufactured by Tonen ■, see Japanese Patent Application No. 62-202765 for the manufacturing method, xylene solution containing 38.2%) 152 g with an internal volume of 500 cc.
Place in a polyethylene pot and add 98 g of mullite powder (MP-20 manufactured by Chichibu Cement). Finally, add 300 g of cylindrical high alumina cobblestones with a diameter of 12 mm and 51 ul, and close the lid of the pot. The mullite powder is dried at 70 to 80° C. above 48) Irs and cooled before blending.

The pot was mixed at 5 rpm for 16 hours, and the mixture was taken out from the pot and used as an impregnating solution. Pour the impregnating liquid into the impregnating tank, and then prepare a woven fabric sheet (plain weave) using carbon fiber (Tonen Pitch HM-50 (ZF grade), ELL Mold Mold Pitch HM-50, or Toho Rayon Bread Making IM-400). Attach it to the spool stand. The winding speed is set to 3 to 5 cm/secC, and the fiber is wound onto a winding mandrel. In order to uniformly disperse the fibers, the winding tension is controlled so that the fibers are opened with a roll and impregnated.

Before winding onto a take-up spool, hot air at 40 to 50° C. is supplied to the strand immediately after impregnation to partially volatilize the solvent and wind it onto a mandrel in a state where the polysilazane has adhesive properties. The winding thickness is about 10 mm, but since an adhesive material is wound around the mandrel, it is preferable to use a silicone-coated polyester film or to perform fluorine treatment. Prepreg removed from mandrel 1OhmX 100+n
(Fig. 1(a)). On the other hand, in the sheet dipping method,
After cutting a fabric sheet with a thickness of 0.25 mm into a diameter of 100 am.

The fibers were immersed in an impregnating solution, taken out from the immersion solution tank, and laminated one by one with the reference fibers shifted at an intersection angle or a phase angle (θ-45') to obtain a thickness of 13 fins.

Thereafter, the prepreg laminate is cut into any shape, molded using a biaxial pressure press or cold or hot isostatic press (CIP or wIP), and then placed in an oven maintained at 50°C for 24 hours. dry.

The heat treatment for making perhydropolysilazane insoluble and infusible was carried out under N2 gas pressure (~
The treatment is completed at 700° C. at 5 kg f/cd G).

During sintering, the surface of the heat-treated molded product is coated with boron nitride fine powder and masked. The product was placed in a pressure sintering mold made of graphite and sintered under a temperature gradient of 600° C./Hr in an argon stream.

The fired crystals were cut out using a diamond cutter as shown below, and their bending strength, fracture toughness, fracture work, etc. were measured. The results are shown in Table 1.

As the rod-shaped sample for measurement, a 2D woven fiber woven prepreg according to the example was used, which was cut out so that the longitudinal direction of the rod-shaped sample was parallel to the - fiber orientation (Fig. 1). reference). In this case, each sheet is immersed at a phase angle or intersection angle of θ-456 based on the sheet dipping method.
Regarding the prepreg (indicated by r2D45°) formed by laminating the fibers, the "fiber orientation" refers to the -th layer.

(Left below) The crystalline phase of the matrix determined by X-ray diffraction is Sil□Af
f,s Oss N8. 3 At! 203 ・25
2, which was i02 (Example-2) First, an impregnating liquid for matrix preparation is prepared.

Chisso #@ polysilazane (product name NCP-・200) in 87.4 g of toluene (solvent). Toluene solution 6
5%'8) Dissolve 64.8g. Prepare this precept separately (7) and place it in a polyethylene pot with an internal volume of 500cc.

Mullite powder (Chichibu cement'?J month rho-20) 98
Enter g. Finally, add 300 g of cylindrical high alumina cobblestones with a diameter of 12.5 mm and close the lid of the pot.

The mullite powder used is one that has been dried at 70 to 80° C. for 48 hours or more and then cooled before blending.

Hereinafter, in the same manner as in Example 1, fiber-reinforced ceramic composites were manufactured by the sheet winding (S/W) method or the sheet dipping method, and the bending strength, fracture toughness value, and fracture work were measured. are shown in Table 2.

(Left below) The crystalline phase of the matrix according to X-ray diffraction is 5i12A
e】s Oas N m・3A+! 203 ・2
5j02 (Example-3) An impregnating liquid for matrix preparation was prepared. 152 g of perhydropolysilazane solution (manufactured by Tonen ■, containing 38.2% xylene solution) was placed in a polyethylene pot with an internal volume of 500 cc, and 122.5 g of alumina powder (Taimicron TMD, manufactured by Ohma Chemical Co., Ltd.) was first added. Finally, 300g of cylindrical high alumina boulders with a diameter of 12.5 cm.
and close the lid of the pot. Alumina powder is 70~
Use the product that has been dried at 80° C. for 48 hours or more and then cooled.

Hereinafter, sheet winding (
Fiber-reinforced ceramic composites were manufactured by the S/W) method or the sheet dipping method, and the bending strength, fracture toughness, and fracture work were measured, and the results are shown in Table 3.

(Left below) The crystalline phase of the matrix according to X-ray diffraction is 5i12A
i! 1603. NB・3Al! 203 ・2
5i02 (Example-4) First, an impregnating liquid for matrix preparation is prepared.

Dissolve 84.6 g of polysilazane manufactured by Chisso ■ (product name NCP-200, containing 65% toluene dissolved) in 87.4 g of toluene (solvent).Put this precept into a separately prepared polyethylene pot with an internal volume of 500 cc. .

Alumina powder (Taimicron TMD manufactured by Ohma Chemical Co., Ltd.) 1
Add 22.5g. Finally, add 300 g of cylindrical high alumina cobblestones with a diameter of 12.5 mm and close the lid of the pot. The alumina powder used is one that has been dried at 70 to 80°C for 48 hours or more and then cooled.

Hereinafter, sheet winding (
Fiber-reinforced ceramic composites were manufactured by the Sew method or the sheet dipping method, and the bending strength, fracture toughness value, and fracture work were measured, and the results are shown in Table 4.

(Left below) The crystalline phase of the matrix determined by X-ray diffraction is Sit□Ae
It was xs Owe Ns + At7203.

(Example-5) An impregnating liquid for matrix preparation is prepared. Verhydropolysilazane solution (manufactured by Tonen ■, containing 38.2% xylene solution) 152. First, silicon nitride powder (manufactured by Ube Industries, Ltd. E-
10) Add 21.5 g and 93.1 g of alumina powder (Taimicron TMD manufactured by Ohma Chemical). Finally, add 300 g of cylindrical high alumina cobblestones with a diameter of 12.5 am and close the lid of the pot. Each ceramic powder is used after being dried at 70 to 80°C for 48 hours or more and then cooled.

Hereinafter, sheet winding (
Fiber-reinforced ceramic composites were produced by the Sew method or the sheet dipping method, and the bending strength, fracture toughness, and work of fracture were measured, and the results are shown in Table 5.

(Left below) According to X-ray diffraction, the crystalline phase of the matrix is approximately 5i.
12Aj! It was tsOs, Ns.

(Example-6) An impregnating liquid for matrix preparation is prepared. Toluene (solvent) 87.4g - polysilazane made by Chisso ■ (product name NCP-200, product containing 65% toluene solution) [i4
．． Dissolve 8g. Internal volume of this liquid prepared separately: 50
It is placed in a 0 cc polyethylene pot, and 21.5 g of silicon nitride powder (E-10 manufactured by Ube Industries) and 93.3 g of alumina powder (Taimicron TMD manufactured by Ozeki Chemical) are placed therein.

Finally, add 300g of cylindrical high alumina cobblestones with a diameter of 12.5 fins and close the lid of the pot. Each ceramic powder is used after being dried at 70 to 80°C for 48 hours or more and then cooled.

Hereinafter, sheet winding (
Fiber-reinforced ceramic composites were produced by the S/W method or the sheet dipping method, and the bending strength, fracture toughness, and fracture work were measured, and the results are shown in Table 6.

The crystalline phase of the matrix determined by X-ray diffraction is approximately Si+2
At! ts 08o Ns〇(Example-7
) Create an impregnating solution for matrix creation. 152 g of perhydropolysilazane solution (manufactured by Tonen ■, containing 38.2% xylene solution) was placed in a polyethylene pot with an internal volume of 500 cc, and then silicon nitride powder (manufactured by Ube Industries, Ltd. E-
10) Add 78.5 g and 24.0 g of alumina powder (Taimicron TMD manufactured by Ozeki Chemical Co., Ltd.). Finally, cylindrical high alumina cobblestone 3 with a diameter of 12.5++s
Add 00g and close the lid of the pot. Each ceramic powder is used after being dried at 70 to 80°C for 48 hours or more and then cooled.

Hereinafter, sheet winding (
Fiber-reinforced ceramic composites were produced by the S/W method or the sheet dipping method, and the bending strength, fracture toughness, and fracture work were measured, and the results are shown in Table 7.

(Left below) According to X-ray diffraction, the crystal phase of the matrix is 1700℃
In this case, β-sialon (z-1), a-silicon nitride, and alumina were used. At 1800°C, it was almost β-sialon.

(Example-8) Create an impregnating solution for matrix creation.

Toluene (solvent) 87.4g contains 65% toluene solution of polysilazane manufactured by Chisso (product name NCP-200) B4. Dissolve Bg. This liquid was poured into a separately prepared polyethylene pot with an internal volume of 500 cc, and then silicon nitride powder (Ube Industries type E-10) was added to the pot.
g.

and alumina powder (Taimicron TMD manufactured by Ohma Chemical Co., Ltd.
) Add 24.0g. Finally, add 300 g of cylindrical high alumina cobblestones with a diameter of 12.5 mm and close the lid of the pot. Each ceramic powder is used after being dried at 70 to 80°C for 48 hours or more and then cooled.

Hereinafter, sheet winding (
Fiber-reinforced ceramic composites were produced by the S/W method or the sheet dipping method, and the bending strength, fracture toughness, and fracture work were measured, and the results are shown in Table 8.

Table (blank below) According to X-ray diffraction, the crystal phase of the matrix is 1700℃
In this case, β-sialon (z-1), α-silicon nitride, and alumina were used. At 1800°C, it was almost β-sialon.

(Example 9) First, an impregnating liquid for matrix preparation is prepared. 152 g of perhydropolysilazane solution (manufactured by Tonen ■, containing 38.2% xylene solution) was placed in a polyethylene pot with an internal volume of 500 cc.
-0A) Insert 98. Finally, add 300 g of cylindrical high alumina cobblestones with a diameter of 12.5 mm and close the lid of the pot.

Hereinafter, sheet winding (
A fiber-reinforced ceramic composite material was produced by the S/W method or the sheet dipping method. However, the sintering temperature was 1B50° C.)9 The bending strength, fracture toughness value, and fracture work were measured, and the results are shown in Table 9.

(The following is a blank space) Table 9 According to X-ray diffraction, the crystal phases of the matrix were β-silicon nitride and α-silicon nitride (partially silicon oxynitride).

(Example 10) First, an impregnating liquid for matrix preparation is prepared. Polysilazane (NC made by Chisso) was added to 87.4 g of toluene (solvent).
P-200 containing 65% toluene solution > 84.8g
dissolve. This liquid was prepared separately with an internal volume of 500 cc.
into a polyethylene pot, and silicon nitride powder (CC-0A manufactured by Ube Industries, Ltd.) 98 is added thereto. Finally, diameter 12,5
Add 300g of am's cylindrical high alumina cobblestone and close the lid of the pot.

Hereinafter, sheet winding (
A fiber-reinforced ceramic composite material was produced by the S/W method or the sheet dipping method (sintering temperature was 1650° C.).1 The bending strength, fracture toughness value, and fracture work were measured, and the results are shown in Table 10.

(The following is a blank space) Table 10 According to X-ray diffraction, the crystal phases of the matrix were β-silicon nitride and α-silicon nitride (partially silicon oxynitride).

As a general summary, sheets and
It is possible to manufacture a homogeneous composite material by a winding (S/W) molding method or a sheet dipping method. Therefore, it is possible to provide a fiber-reinforced ceramic composite material that has no anisotropy in the x-y directions and has stable fracture toughness, fracture work, etc.

In particular, the composite material obtained by stacking each prepreg made by the sheet dipping method with a phase angle or intersection angle of θ-45a has further reduced directionality and improved physical properties such as fracture toughness. It becomes what is given.

[Effect of the invention] Brittleness, which was said to be a drawback of ceramic materials.

By reinforcing long fibers in the same direction in a plane, the fracture toughness value of monolithic material can be increased by 2 to 4 times, and the work of fracture can be increased by approximately 1000.
This can be improved by a factor of two, and the anisotropy of the composite object can be significantly reduced.

Applications of composite materials obtained from these things include reciprocating engines, gas turbine engines, aerospace aircraft materials,
It has become possible to apply it to fields that were previously considered impossible with monolithic materials, such as aerospace engine materials and brake materials.

Incidentally, as a side effect of using a predetermined preceramic polymer, 81 can be diffused into the fibers used, and for example, in the case of carbon fibers, the surface can be made into silicon carbide.
Oxidation resistance can be improved.

[Brief explanation of drawings]

FIG. 1 is a plan view showing the relationship between the fiber orientation direction and the prepreg cut-out direction for a physical property measurement sample having a 2D woven fiber texture and a 2D fiber structure according to an example. FIG. 2 is a schematic diagram showing a sheet winding method (S-winding method), which is one step of the manufacturing process according to the present invention. FIG. 3 is a schematic diagram showing a sheet dipping method, which is one step of the manufacturing process according to the present invention, and FIG. 4 is a plan view showing a method of laminating prepreg sheets obtained by the sheet dipping method. respectively. Applicant Noritake Co., Ltd.
Name) Agent Patent Attorney Kato Asa Michi Figure 1 (Yu1 regular offering letter cut out one layer) Figure 2 21'') j1 Ao's meat arrangement

Claims (6)

[Claims] (1) One or more ceramic powders selected from the group consisting of mullite, alumina, and silicon nitride are added to a solution consisting of a preceramic polymer containing silicon and nitrogen as essential components and having an inorganic material or a total number of carbon atoms in the main repeating unit of 7 or less. A step of adjusting the blended impregnating liquid, a step of passing a continuous sheet of woven fibers through the impregnating liquid to obtain a prepreg laminate having a two-dimensionally oriented fiber structure, and a step of placing the prepreg laminate in an inert gas or nitrogen gas atmosphere. A method for producing a fiber-reinforced ceramic composite material, comprising the steps of: primary heat treatment at 400 to 700°C in the same atmosphere, and then secondary heat treatment at 1500 to 1800°C in the same atmosphere under normal pressure or pressure. (2) One or more ceramic powders selected from the group consisting of mullite, alumina, and silicon nitride are added to a solution consisting of a preceramic polymer containing silicon and nitrogen as essential components and having an inorganic material or a total number of carbon atoms in the main repeating unit of 7 or less. A process of adjusting the blended impregnating liquid, A process of immersing a fabric unit sheet of fibers in an impregnating liquid to obtain a prepreg sheet having a two-dimensionally oriented fiber structure, A process of sequentially stacking the prepreg sheets with their fiber orientation directions crossing each other. A step of forming the prepreg laminate into a prepreg laminate of any shape, and a primary heat treatment of the prepreg laminate at 400 to 700°C in an inert gas or nitrogen gas atmosphere, followed by heating at 1500 to 1800°C in the same atmosphere at normal pressure or A method for producing a fiber-reinforced ceramic composite material, comprising the steps of performing secondary heat treatment under pressure. (3) The manufacturing method according to claim 2, wherein in the step of forming the prepreg laminate, the intersection angle θ of the orientation direction of the fibers satisfies 0<θ<90°. (4) The manufacturing method according to claim 1 or 2, wherein the preceramic polymer is a perhydropolysilazane having a main repeating unit ▲ which has a mathematical formula, chemical formula, table, etc. ▼. (5) Preceramic polymer is the main repeating unit ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (R is an alkyl group with 7 or less carbon atoms, an alkenyl group, an aryl group, a cycloalkyl group, an alkylsilyl group, an alkylamino group, or The manufacturing method according to claim 1 or 2, wherein the polysilazane is a polysilazane (representing an alkoxy group). (6) The manufacturing method according to claim 1 or 2, wherein the fibers are carbon fibers.