Ceramic matrix composite material and method for manufacturing the same

Abstract

To provide at least one of: a ceramic matrix composite material that has strength equivalent to that of a conventional CMC without stacking a large number of ceramic continuous fiber cloths; and a method for manufacturing the same.SOLUTION: A ceramic matrix composite material comprises a ceramic matrix and a ceramic continuous fiber cloth, has a fiber volume ratio of 35% or less, and has a thickness of less than 0.5 mm.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to ceramic matrix composites and methods for making same. [Background technology]

[0002] Ceramic matrix composites (hereinafter referred to as "CMCs"), which combine continuous ceramic fibers with a ceramic matrix, are more resistant to overall material destruction caused by the progression of flaws than ordinary ceramics. For this reason, CMCs are being studied as a replacement for heat-resistant metals such as Ni-based alloys, and are expected to be used as components for aircraft jet engines, for example.

[0003] As components for aircraft jet engines, for example, Patent Document 1 discloses a CMC made of a ceramic continuous fiber cloth containing ytterbium silicate and a silicon carbide matrix, while Patent Document 2 discloses a CMC made of an oxide ceramic continuous fiber cloth and a mullite and alumina matrix. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2010 / 143608 [Patent Document 2] Japanese Patent Application Laid-Open No. 2008-024585 Summary of the Invention [Problem to be solved by the invention]

[0005] The CMCs disclosed in Patent Documents 1 and 2 both exhibit high strength. However, both CMCs achieve high strength by stacking multiple ceramic continuous fiber cloths. Because of this structure, these CMCs are thick, which limits the shapes of components to which they can be applied.

[0006] An object of the present disclosure is to provide at least one ceramic matrix composite material that has strength equivalent to that of conventional CMCs without stacking a large number of ceramic continuous fiber cloths, and a method for producing the same. [Means for solving the problem]

[0007] In this disclosure, we have investigated how to increase the strength of CMCs, and as a result, we have confirmed that when the number of layers of ceramic continuous fiber cloth is reduced, the strength of the CMC decreases significantly as the number of layers decreases.

[0008] Furthermore, by focusing on the relationship between the ceramic continuous fiber cloth and the ceramic matrix, we investigated ways to improve the strength of CMCs and found that by controlling the interface between the ceramic continuous fiber cloth and the ceramic matrix, it is possible to obtain a CMC with the same strength as a CMC obtained by stacking a large number of ceramic continuous fiber cloths, without having to stack a large number of ceramic continuous fiber cloths.

[0009] That is, the present invention is as defined in the claims, and the gist of the present disclosure is as follows. [1] A ceramic matrix composite material comprising a ceramic matrix and a ceramic continuous fiber cloth, having a fiber volume fraction of 35% or less and a thickness of less than 0.5 mm. [2] The ceramic matrix composite material according to [1] above, which comprises one to three sheets of the ceramic continuous fiber cloth. [3] The ceramic matrix composite material according to [1] or [2] above, wherein the ceramic matrix is ​​one or more selected from the group consisting of alumina, mullite, silica, and zirconia. [4] The ceramic matrix composite material according to any one of [1] to [3] above, wherein the ceramic continuous fiber cloth is a ceramic continuous fiber cloth made of one or more ceramic continuous fibers selected from the group consisting of alumina, mullite, alumina and mullite, and alumina and silica. [5] The ceramic matrix composite material according to any one of [1] to [4] above, wherein the ceramic continuous fiber cloth contains an α-alumina structure in its crystal structure and has an Al2O3 content of 60 mass % or more and 100 mass % or less. [6] A method for producing a ceramic matrix composite material according to any one of [1] to [5] above, comprising the steps of: mixing a slurry having a pH of 2.0 or more and 7.5 or less, containing a ceramic matrix source, with a ceramic continuous fiber cloth to obtain a mixture; solidifying the mixture to obtain a molded body; and firing the molded body. [7] The manufacturing method according to [6] above, wherein the viscosity of the slurry containing the ceramic matrix source is 50 mPa·s or more and 2000 mPa·s or less. [8] A member comprising the ceramic matrix composite material according to any one of [1] to [5] above. [Effects of the Invention]

[0010] The present disclosure makes it possible to provide at least one ceramic matrix composite material and a method for producing the same that has strength equivalent to that of a conventional CMC without stacking a large number of ceramic continuous fiber cloths. [Brief explanation of the drawings]

[0011] [Figure 1] Appearance of CMC in Example 3 DETAILED DESCRIPTION OF THE INVENTION

[0012] The ceramic continuous fiber of the present disclosure will be described with reference to an example embodiment. The terms used in this embodiment are as follows. The present disclosure also includes any combination of the configurations and parameters disclosed herein, as well as any combination of the upper and lower limits of the values ​​disclosed herein.

[0013] "Ceramic matrix composites" (CMCs) are materials that combine ceramic continuous fiber cloth with a ceramic matrix, and are so-called ceramic fiber-reinforced ceramics.

[0014] A "ceramic matrix" is a ceramic that serves as the matrix (parent phase) of a CMC, and is essentially a matrix (parent phase) of a CMC that is composed of ceramic crystal particles (hereinafter simply referred to as "crystal particles").

[0015] "Ceramic continuous fiber cloth" refers to a woven fabric of ceramic fibers, and further to a woven fabric of ceramic continuous fibers, a woven fabric of fiber bundles of ceramic continuous fibers, that is, ceramic continuous fibers in a woven state of fiber bundles.

[0016] "Ceramic fiber" refers to a spun polycrystalline ceramic, or even a filamentous polycrystalline ceramic, and is a fiber composed of crystal particles. Ceramic fibers are classified into "ceramic short fiber" and "ceramic continuous fiber" depending on their fiber length. In this embodiment, "ceramic short fiber" refers to a ceramic fiber with a fiber length of less than 500 μm, and "ceramic continuous fiber" refers to a ceramic fiber other than ceramic short fiber (ceramic fiber with a fiber length of 500 μm or more). Furthermore, "ceramic mixed fiber" refers to a ceramic fiber having a mixed structure of crystal particles of two or more types of ceramics, and "ceramic mixed continuous fiber" refers to a ceramic continuous fiber having a mixed structure of crystal particles of two or more types of ceramics.

[0017] A "fiber bundle" is an assembly of two or more ceramic fibers.

[0018] "Fiber volume fraction" is the volume percentage [volume %] of ceramic continuous fiber cloth in the CMC. The fiber volume fraction can be calculated using the following formula:

[0019] Fiber volume fraction [volume%] = (V f / V CMC ) x 100 In the above equation, V f is the volume of the ceramic continuous fiber, and V CMC is the volume of the CMC. Also, V f and V CMC are calculated from the following formulas, respectively.

[0020] V f = m / ρ f V CMC = A×B×t CMC In the above formula, m is the mass of the ceramic continuous fiber cloth [g] and ρ f is the density of the ceramic continuous fiber cloth [g / cm 3 ], and A is the length of the CMC [cm], B is the width of the CMC [cm], and t CMC is the thickness of the CMC [cm].

[0021] "Measured density" is the mass [g / cm3] measured using an electronic balance in accordance with JIS R 1634, relative to the volume calculated by Archimedes' method. 3 ] is the density obtained from

[0022] The "average particle size" is the median size (D50) in the volume particle size distribution of the powder measured by a wet method.

[0023] The "BET specific surface area" is the BET specific surface area measured in accordance with JIS Z 8830, and may be measured by a BET single-point method using nitrogen as the carrier gas adsorption gas, using a general gas adsorption measurement device (e.g., BELSORP MR6, manufactured by MICROTRAC). Specific measurement conditions for the BET specific surface area include, for example, the following:

[0024] Adsorption medium: N2 Adsorption temperature: -196℃ Pretreatment conditions: Treatment in air at 200°C for 25 minutes "Tensile strength" is a value determined using a standard strength testing machine (e.g., Shimadzu AG-XPlus) and tensile test jig according to a method conforming to JIS R 1656. A CMC measuring 10±1 mm wide x 110±10 mm long with aluminum tabs attached to both ends is used as the measurement sample. The tensile strength is measured twice at a loading rate of 0.5 mm / min, and the average value obtained is used as the tensile strength. If the CMC is 1 mm or thicker, it is sufficient to process the CMC to a thickness of 1 mm or thicker but not thicker than 3 mm. If the CMC is less than 1 mm thick, processing in the thickness direction is not required. [Ceramic matrix composites (CMC)] This embodiment is a ceramic matrix composite material that includes a ceramic matrix and a ceramic continuous fiber cloth, has a fiber volume fraction of 35% or less, and has a thickness of less than 0.5 mm. This provides a scratch propagation suppression effect that differs from the scratch propagation suppression effect achieved by laminating multiple fiber cloths, and is believed to have strength equivalent to that of conventional CMCs that are made up of multiple fiber cloths.

[0025] The CMC of this embodiment has a fiber volume fraction of 35% or less. The fiber volume fraction is one of the indicators that indicates the state of the interface between the ceramic continuous fiber cloth (hereinafter simply referred to as "fiber cloth") and the ceramic matrix (hereinafter simply referred to as "matrix") in the CMC. With the above-mentioned fiber volume fraction, it is believed that the CMC of this embodiment has improved interfacial strength between the fiber cloth and the matrix, and suppresses the progression of scratches.

[0026] Since the tensile strength of the CMC tends to be high, the fiber volume fraction is preferably 32% or less, more preferably 30% or less, or even 28% or less. If the content of fiber cloth in the CMC is too low, the tensile strength of the CMC tends to be low. Therefore, the lower limit of the fiber volume fraction may be 5% or more, 7% or more, or 10% or more. The fiber volume fraction of the CMC of this embodiment may be 5% or more and 35% or less, 7% or more and 32% or less, or 10% or more and 28% or less.

[0027] The CMC of this embodiment has a thickness (hereinafter also referred to as "CMC thickness") of less than 0.5 mm. A CMC thickness of less than 0.5 mm results in a CMC that exhibits sufficient elasticity to prevent cracking even when bending, such as warping, when used in membranes, filters, etc. Since this tends to exhibit high elasticity, the CMC thickness is preferably 0.48 mm or less, 0.45 mm or less, 0.40 mm or less, or 0.37 mm or less. Since the CMC thickness is greater than or equal to the thickness of the fiber cloth, the lower limit depends on the thickness of the fiber cloth. Examples of the lower limit of the CMC thickness include more than 0.05 mm, 0.10 mm or more, or 0.12 mm or more. Examples of the CMC thickness of the CMC of this embodiment include more than 0.05 mm but less than 0.50 mm, 0.10 mm or more but 0.45 mm or less, or 0.12 mm or more but 0.40 mm or less.

[0028] The CMC thickness may be determined by measuring the thickness of the CMC at three points using a micrometer and averaging the measurements.

[0029] The CMC of this embodiment preferably has a CMC thickness sufficient to provide the above-described elasticity, and the effect of inhibiting scratch progression due to the lamination of fiber cloths is not essential. Therefore, the CMC of this embodiment may contain one to three fiber cloths, or even one to two fiber cloths, and may even contain one fiber cloth. When the CMC of this embodiment contains two or more fiber cloths, the fiber cloths are laminated, forming a fiber cloth laminate structure. In this case, the fiber cloths may be laminated directly, or may be laminated via a matrix.

[0030] The fiber cloths contained in the CMC of this embodiment can be observed using a digital microscope. A cross section of the CMC cut in the thickness direction can be observed using a digital microscope (e.g., VHX-6000, manufactured by Keyence Corporation), and the number of fiber cloth layers observed in the thickness direction of the CMC can be determined from the obtained observation image. The magnification for digital microscope observation can be, for example, 200 times or more and 500 times or less.

[0031] The fiber cloth in the CMC of this embodiment is a component that reinforces the matrix. The fiber cloth is not particularly limited as long as it is a continuous fiber cloth made of ceramic, and may be made of either the same or a different ceramic as the matrix. The fiber cloth is preferably made of the same ceramic as the matrix, since this appropriately increases the interfacial strength between the fiber cloth and the matrix and facilitates suppression of interfacial delamination. The fiber cloth contained in the CMC of this embodiment is preferably a fiber cloth made of one or more ceramic continuous fibers selected from the group consisting of silicon carbide, alumina, mullite, zirconia, alumina and mullite, alumina and silica, and alumina, silica, and boron oxide (hereinafter, fiber cloths made of alumina, etc., are also referred to as "alumina continuous fiber cloths" or the like). It is more preferably a fiber cloth made of one or more ceramic continuous fibers selected from the group consisting of alumina, mullite, alumina and mullite, and alumina and silica. It is even more preferably a fiber cloth made of one or more ceramic continuous fibers selected from the group consisting of alumina, mullite, alumina and mullite, and alumina and silica.

[0032] The fiber cloth is preferably an alumina continuous fiber cloth, since the CMC of this embodiment exhibits higher tensile strength.

[0033] In order for the CMC of this embodiment to exhibit higher heat resistance, the fiber cloth is preferably one or more types selected from the group consisting of alumina continuous fiber cloth, mullite continuous fiber cloth, and alumina and mullite continuous fiber cloth, and more preferably alumina and mullite continuous fiber cloth.

[0034] In order to further reduce the weight of the CMC of this embodiment, the fiber cloth is preferably at least one of an alumina and silica continuous fiber cloth and an alumina and mullite continuous fiber cloth, and more preferably an alumina and silica continuous fiber cloth.

[0035] A preferred alumina continuous fiber cloth is a fiber cloth having an α-alumina structure in its crystalline structure and an Al2O3 content of 60% by mass or more and 100% by mass or less, or a fiber cloth having an α-alumina structure in its crystalline structure and an Al2O3 content of 80% by mass or more and less than 100% by mass.

[0036] A preferred alumina and silica continuous fiber cloth is a fiber cloth containing a γ-alumina structure and amorphous silica, and having an Al 2 O 3 content of 60% by mass or more and 85% by mass or less and an SiO 2 content of more than 15% by mass but less than 40% by mass.

[0037] Preferable alumina and mullite continuous fiber cloths include fiber cloths having an α-alumina structure and a mullite structure as a crystal structure, and an Al2O3 content of 80% by mass or more and 95% by mass or less and an SiO2 content of more than 5% by mass and less than 20% by mass.

[0038] The surface density of the fiber cloth is 50 g / m 2 More than 70g / m 2 More than 100g / m 2 or more than 250g / m 2 and above 1000g / m 2 Below, 950g / m 2 Below 900g / m 2 or less than 700g / m 2 For example, it can be 70 g / m or less. 2 More than 950g / m 2 or less than 100g / m 2 More than 900g / m 2 The following is fine.

[0039] The ceramic continuous fibers constituting the fiber cloth preferably have a fiber diameter of 3 μm or more, 4 μm or more, or 5 μm or more, and 20 μm or less, 18 μm or less, or 15 μm or less, and may be 3 μm or more and 20 μm or less, or 4 μm or more and 15 μm or less.

[0040] The thickness of the fiber cloth is 0.05 mm or more, 0.08 mm or more, 0.10 mm or more, 0.12 mm or more, or 0.15 mm or more, and 0.40 mm or less, 0.35 mm or less, 0.30 mm or less, or 0.25 mm or less, such as 0.05 mm or more and 0.40 mm or less, 0.08 mm or more and 0.30 mm or less, 0.10 mm or more and 0.25 mm or less, or 0.10 mm or more and 0.20 mm or less.

[0041] The thickness of the fiber cloth included in the CMC of this embodiment can be measured by digital microscope observation. A cross section of the CMC cut in the thickness direction is observed with a digital microscope (e.g., VHX-6000, manufactured by Keyence Corporation), and the thickness of the fiber cloth observed in the thickness direction of the CMC in the obtained observation image is measured at three points, and the average value is taken as the thickness of the fiber cloth. The observation magnification in the digital microscope observation can be, for example, 200 times or more and 500 times or less.

[0042] The fiber cloth contained in the CMC of this embodiment may have any thickness and number (number of layers) as long as the CMC thickness is less than 0.50 mm, and the CMC thickness decreases as the thickness and number of fiber cloths decrease. The CMC of this embodiment may include two fiber cloths each having a thickness of 0.10 mm or more and 0.20 mm or less, or may further include two laminated fiber cloths each having a thickness of 0.10 mm or more and 0.20 mm or less.

[0043] The matrix is ​​a component reinforced by continuous ceramic fibers in a CMC. The matrix (specifically, the crystal grains constituting the matrix) is at least one of an oxide ceramic and a non-oxide ceramic, preferably an oxide ceramic, more preferably one or more selected from the group consisting of alumina, mullite, silica, and zirconia, even more preferably one or more selected from the group consisting of alumina, mullite, and zirconia, still more preferably at least one of alumina and mullite, and preferably contains at least alumina.

[0044] The zirconia contained in the CMC of this embodiment may be zirconia having a stabilizing element dissolved therein, preferably zirconia having yttrium dissolved therein, more preferably zirconia having 2 mol % to 10 mol % of yttrium dissolved therein in terms of Y2O3, even more preferably zirconia having 2 mol % to 4 mol % of yttrium dissolved therein in terms of Y2O3, and even more preferably zirconia having 2.5 mol % to 3 mol % of yttrium dissolved therein in terms of Y2O3 (hereinafter, zirconia having X mol % of yttrium dissolved therein will also be referred to as "XYSZ", and for example, zirconia having 3 mol % of yttrium dissolved therein will also be referred to as "3YSZ").

[0045] The matrix is ​​preferably alumina, since this increases the strength of the CMC of this embodiment. Furthermore, the matrix is ​​preferably at least one of alumina and mullite, and more preferably mullite, since this increases the heat resistance of the CMC of this embodiment. When the crystal particles are at least one of alumina and mullite, or even alumina, or even α-alumina, the CMC of this embodiment exhibits higher strength and heat resistance. The matrix is ​​preferably zirconia, since this increases the oxygen permeability of the CMC of this embodiment.

[0046] The CMC of this embodiment includes a fiber cloth and a matrix, and may consist of a fiber cloth and a matrix, but in addition to the fiber cloth and matrix, it may also include an additive, and preferably includes a substance that has the function of suppressing the progress of sintering between the crystal particles and the ceramic continuous fibers during heat treatment.

[0047] It is sufficient that at least a portion of the additive is contained in the matrix, and it is preferable that the entire additive is contained in the matrix, which makes it easier to suppress the growth of crystal grains in the ceramic that constitutes the matrix during the production of the CMC of this embodiment.

[0048] The additive may be any compound having a different composition from the matrix. Examples of the additive include one or more selected from the group consisting of silica (SiO), zirconia (ZrO), yttria (YO), ytterbium oxide (YbO), and mullite (3AlO·2SiO). The additive is preferably one or more selected from the group consisting of silica, zirconia, yttria, and ytterbium oxide, and more preferably at least one of silica and zirconia. The zirconia contained as the additive may be zirconia with yttrium dissolved therein, preferably zirconia with 2 mol% to 10 mol% of yttrium dissolved therein (calculated as YO), more preferably zirconia with 2 mol% to 4 mol% of yttrium dissolved therein (calculated as YO), and even more preferably zirconia with 2.5 mol% to 3 mol% of yttrium dissolved therein (calculated as YO).

[0049] The CMC of this embodiment may contain 1 to 5 types of additives, 1 to 3 types of additives, 1 to 2 types of additives, or 1 type of additive.

[0050] In this embodiment, the mass ratio of the fiber cloth to the mass of the CMC (hereinafter also referred to as "fiber content") is 25% by mass or more, 30% by mass or more, 38% by mass or more, or 40% by mass or more, and 65% by mass or less, 60% by mass or less, 55% by mass or less, or 52% by mass or less. Preferred fiber contents are 25% by mass or more and 65% by mass or less, 30% by mass or more and 65% by mass or less, or 38% by mass or more and 55% by mass or less.

[0051] In this embodiment, the ratio of the mass of the matrix to the mass of the CMC (hereinafter also referred to as "matrix content") is less than 75 mass%, 70 mass% or less, 65 mass% or less, or 60 mass% or less, and may also be greater than 35 mass%, 40 mass% or more, 45 mass% or more, or 47 mass% or more. Preferred matrix contents include greater than 35 mass% and less than 75 mass%, 40 mass% or more to 65 mass% or less, or 45 mass% or more to 60 mass% or less.

[0052] Furthermore, the mass of the additive relative to the mass of the CMC in this embodiment (hereinafter also referred to as "additive content") is greater than 0 mass%, 0.1 mass% or more, 0.2 mass% or more, or 0.5 mass% or more, and may be 3 mass% or less, 2.5 mass% or less, 2.0 mass% or less, or 1.5 mass% or less.

[0053] The fiber content, matrix content, and additive content may be determined as follows.

[0054] Fiber content [mass%] = {Mass of fiber cloth [g] / Mass of CMC [g]} x 100 Matrix content [mass%] = 100 - {fiber content [mass%] + additive content [mass%]} Additive content [mass%] = {additive mass [g] / CMC mass [g]} x 100 The mass of the fiber cloth is calculated by dividing the mass of the CMC [g] by the density of the ceramic continuous fiber [g / cm 3 The mass of the additive is calculated as the oxide mass of the additive, which is determined from EDS mapping of the matrix observed on the CMC cross section.

[0055] The EDS mapping measurement can be performed using a general field emission scanning microscope (FE-SEM, for example, JSM-7600F, manufactured by JEOL Ltd.) equipped with an energy dispersive characteristic X-ray analyzer. The following conditions can be given as examples of the conditions for FE-SEM observation.

[0056] Accelerating voltage: 7 kV Observation magnification: 5000x The measurement sample can be prepared by cutting the CMC with a diamond blade and preparing an observation surface using an Ar beam cross-section polisher.

[0057] The measured density of the CMC of this embodiment varies depending on the type of matrix and fiber cloth, and is, for example, 2.20 g / cm 3 More than 3.20g / cm3 or less, or 2.25 g / cm 3 More than 3.00g / cm 3 The following are included:

[0058] The tensile strength of the CMC of this embodiment varies depending on the type of matrix and fiber cloth, but is, for example, 80 MPa or more, 100 MPa or more, 110 MPa or more, or 150 MPa or more, and can be 400 MPa or less, 350 MPa or less, 300 MPa or less, 280 MPa or less, or 250 MPa or less, and examples thereof include 100 MPa or more and 400 MPa or less, or 110 MPa or more and 350 MPa or less.

[0059] The CMC of this embodiment can be used for known CMC applications, including components and heat-resistant components, such as heat-resistant structural materials, fire-prevention materials, and heat-resistant filters, turbine components, and nuclear-related components. The CMC of this embodiment can also be used for applications requiring electrical insulation, such as battery separators. The CMC of this embodiment can also be used for at least one of the insulating material and electrolyte of solid oxide fuel cells. [Method for manufacturing ceramic matrix composites] The ceramic matrix composite material of this embodiment can be produced by any method as long as it has the above-mentioned characteristics. A preferred method for producing the ceramic matrix composite material of this embodiment is a method for producing a ceramic matrix composite material (hereinafter also referred to as the "production method of this embodiment") that includes the steps of mixing a slurry containing a ceramic matrix source and having a pH of 2.0 to 7.5 with a ceramic continuous fiber cloth to obtain a mixture, solidifying the mixture to obtain a molded body, and firing the molded body.

[0060] The manufacturing method of this embodiment includes a step of mixing a slurry (hereinafter also referred to as "raw material slurry") having a pH of 2.0 or more and 7.5 or less and containing a ceramic matrix source (hereinafter also referred to as "matrix source") with a ceramic continuous fiber cloth to obtain a mixture.

[0061] The mixing method may be any method, for example, impregnating a fiber cloth with the raw material slurry, and specifically, at least one of vacuum impregnation and pressure impregnation may be used. When two or more fiber cloths are used, it is preferable to impregnate the raw material slurry with the fiber cloths stacked one on top of the other.

[0062] The vacuum impregnation treatment may be carried out under the following conditions.

[0063] Impregnation atmosphere: Vacuum degree 85% or more or vacuum degree 90% or more, and Vacuum degree 100% or less, vacuum degree less than 100%, or vacuum degree 99% or less Impregnation temperature: 0°C or higher or 10°C or higher, and Below 40℃ or below 35℃ The pressure impregnation treatment may be carried out under the following conditions.

[0064] Impregnation pressure: 0.11 MPa or more or 0.15 MPa or more, and 2.0MPa or less or 1.8MPa or less Impregnation temperature: 0°C or higher or 10°C or higher, and Below 40℃ or below 35℃ A preferred example of the mixing method is to impregnate the fiber cloth with the raw material slurry at room temperature under a vacuum of 90% or more, or further under a vacuum of 95% or more but less than 100% at 25±5° C. When two or more fiber cloths are used, a preferred example of the mixing method is to stack the fiber cloths and impregnate them with the raw material slurry at room temperature under a vacuum of 90% or more, or further under a vacuum of 95% or more but less than 100% at 25±5° C.

[0065] The pH of the raw material slurry is 2.0 or more and 7.5 or less. By setting the pH of the raw material slurry within this range, a raw material slurry in which the matrix source and the like are uniformly dispersed in the solvent can be obtained, and the raw material slurry is uniformly distributed throughout the fiber cloth, and the fiber cloth is uniformly infiltrated with the raw material slurry. Since the raw material slurry can more easily infiltrate into the interior of the fiber cloth, the pH of the raw material slurry is preferably 2.5 or more, 3.0 or more, or 3.5 or more, and 7.0 or less, 6.0 or less, 5.5 or less, or 5 or less, and more preferably 2.5 or more and 6.0 or less, or even 3.0 or more and 5.5 or less.

[0066] The pH may be adjusted by any method, for example, by mixing a pH adjuster with the raw slurry. The pH adjuster may be one or more selected from the group consisting of nitric acid, hydrochloric acid, and hydrogen peroxide, and is preferably at least one of nitric acid and hydrochloric acid.

[0067] A preferred method for adjusting the pH is to mix diluted nitric acid having a pH of 1 or more and 3 or less with the raw material slurry.

[0068] The viscosity of the raw material slurry is preferably 50 mPa·s or more, 80 mPa·s or more, 100 Pa·s or more, or 200 mPa·s or more, and 2000 mPa·s or less, 1800 mPa·s or less, 1600 mPa·s or less, 1500 mPa·s or less, 1000 mPa·s or less, or 500 mPa·s or less, and examples thereof include 50 mPa·s or more and 2000 mPa·s or less, 80 mPa·s or more and 1800 mPa·s or less, and even 100 mPa·s or more and 1500 mPa·s or less. By setting the viscosity of the raw material slurry within this range, the raw material slurry can be more easily distributed uniformly throughout the fiber cloth.

[0069] The viscosity of the slurry may be measured using a B-type rotational viscometer (for example, TVB-10 viscometer, manufactured by Toki Sangyo Co., Ltd.) in accordance with the viscosity measurement method using a single-cylinder rotational viscometer of JIS Z 8803. Examples of measurement conditions include the following:

[0070] Rotation speed: 12 rpm SPINDLE No.: M2 Container: 500ml tall beaker The raw material slurry contains a matrix source, preferably a matrix source and an additive source, more preferably a solvent in addition to the matrix source and the additive source. The matrix source may be a CMC matrix or a precursor thereof, and is preferably one or more selected from the group consisting of alumina, mullite, silica, and zirconia, more preferably one or more selected from the group consisting of alumina, mullite, and zirconia, further preferably at least one of α-alumina and mullite, and even more preferably α-alumina.

[0071] The matrix source may be in any state that contains the raw material of the desired matrix and is dispersible in the raw material slurry, and is preferably at least one of powder and colloidal particles, and more preferably powder. Specific examples of the matrix source include one or more selected from the group consisting of alumina powder, mullite powder, silica powder, and zirconia powder, preferably one or more selected from the group consisting of alumina powder, mullite powder, and zirconia powder, more preferably at least one of α-alumina powder and mullite powder, and even more preferably α-alumina powder.

[0072] The average particle size of the matrix source is, for example, 0.01 μm or more or 0.1 μm or more and 5 μm or less or 3 μm or less, e.g., 0.01 μm or more and 5 μm or less, or 0.1 μm or more and 3 μm or less. When the average particle size satisfies this range, the matrix source is easily dispersed uniformly throughout the fine details of the fiber cloth.

[0073] The BET specific surface area of ​​the matrix source is 0.5 m 2 / g or more, 1m 2 / g or more, 5m 2 / g or more or 8m 2 / g or more and 50m 2 / g or less, 45m 2 / g or less, 40m 2 / g or less, 30m 2 / g or less or 20m2 / g or less, and 0.5m 2 / g or more 50m 2 / g or less, 5m 2 / g or more 40m 2 / g or less, or 5m 2 / g or more 30m 2 When the BET specific surface area satisfies this range, the matrix material can be easily dispersed uniformly throughout the fine details of the fiber cloth.

[0074] The raw slurry may contain an additive source. For example, the raw slurry may contain 1 to 5, 1 to 3, 1 to 2, or 1 additive source.

[0075] The additive source may be any compound having a different composition from the matrix source, and may be a compound containing at least one element selected from the group consisting of silicon (Si), aluminum (Al), zirconium (Zr), yttrium (Y), and ytterbium (Yb). The compound may be at least one element selected from the group consisting of oxides, hydroxides, and chlorides, and is preferably an oxide.

[0076] A preferred additive source is an oxide containing one or more selected from the group consisting of silicon, aluminum, zirconium, yttrium, and ytterbium. Specific examples of the additive source include one or more selected from the group consisting of silica (SiO), zirconia (ZrO), yttria (YO), ytterbium oxide (YbO), and mullite (3AlO·2SiO), with one or more selected from the group consisting of silica, zirconia, yttria, and ytterbium oxide being preferred, and at least one of silica and zirconia being more preferred.

[0077] The additive source is preferably at least one of powder and colloidal particles, more preferably powder. Specific additive sources are preferably at least one selected from the group consisting of silica powder, zirconia powder, yttria powder, ytterbium oxide powder, and mullite powder, more preferably at least one selected from the group consisting of silica powder, zirconia powder, yttria powder, and ytterbium oxide powder, and even more preferably at least one of silica powder and zirconia powder.

[0078] The average particle size of the additive source is 0.01 μm or more, 0.04 μm or more, or 0.1 μm or more, and 10 μm or less, 8 μm or less, or 6 μm or less, for example, 0.01 μm or more and 10 μm or less, or 0.04 μm or more and 6 μm or less. When the average particle size satisfies this range, the additive source is less likely to aggregate in the raw material slurry, and the additive is more likely to be uniformly dispersed and contained in the matrix of the resulting CMC.

[0079] The BET specific surface area of ​​the additive source is 0.5m 2 / g or more, 1m 2 / g or more, 5m 2 / g or more or 8m 2 / g or more and 50m 2 / g or less, 45m 2 / g or less, 40m 2 / g or less, 30m 2 / g or less or 20m 2 / g or less, and 0.5m 2 / g or more 50m 2 / g or less, 5m 2 / g or more 40m 2 / g or less, or 5m 2 / g or more 30m 2 When the BET specific surface area satisfies this range, the additive source can be easily dispersed uniformly throughout the fine details of the fiber cloth.

[0080] The raw material slurry has a mass of the additive source calculated as an oxide (hereinafter also referred to as "additive source amount") relative to the mass of the metal element calculated as an oxide of 0.2 mass% or more, 0.5 mass% or more, or 1.0 mass% or more, and 3.0 mass% or less, 2.5 mass% or less, or 2.0 mass% or less. For example, in the case of a raw material slurry in which the additive source is silica and the matrix source is alumina, the additive source amount can be calculated by {(mass of silica [g]) / (mass of silica + mass of alumina) [g]} × 100.

[0081] The solvent contained in the raw material slurry may be any solvent in which the matrix source and the additive source can be dispersed, and examples thereof include water, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, butyl alcohol, isobutyl alcohol, acetone, methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, cyclohexanone, diacetone alcohol, benzene, toluene, xylene, ethyl acetate, methyl acetate, butyl acetate, methoxybutyl acetate, isobutyl acetate, normal hexane, heptane, cyclohexane, methylcyclohexane, ethylene glycol, and ethylene glycol. Examples of the alcohol include one or more selected from the group consisting of glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, N,N-dimethylformamide, tetrahydrofuran, N-methyl-2-pyrrolidone, 1,4-dioxane, and styrene, and one or more selected from the group consisting of water, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, butyl alcohol, and isobutyl alcohol are preferred, and at least one of water and ethanol is more preferred, with water being even more preferred.

[0082] The raw material slurry may contain a dispersant to disperse the matrix source and the additive source more uniformly in the solvent. Examples of the dispersant include at least one of a dispersant having high affinity with the matrix source and a dispersant having high solubility in the solvent, and examples thereof include one or more selected from the group consisting of anionic polymer dispersants, cationic polymer dispersants, nonionic polymer dispersants, anionic low-molecular-weight dispersants, cationic low-molecular-weight dispersants, nonionic low-molecular-weight dispersants, inorganic acids, and inorganic salts. Specific examples of the dispersant include ammonium polyacrylate, ammonium polymethacrylate, sodium polyacrylate, sodium polymethacrylate, polyethyleneimine, polyethylene glycol, sodium dodecyl sulfonate, sodium dodecylbenzenesulfonate, benzalkonium chloride, distearyldimethylammonium chloride, polyoxyethylene alkyl ether, pentaethylene glycol monododecyl ether, octaethylene glycol monododecyl ether, polyoxyethylene alkyl phenyl ether, dilute nitric acid, dilute hydrochloric acid, dilute sulfuric acid, phosphoric acid, and sodium tripolyphosphate. Specific examples of the dispersant include ammonium polyacrylate, ammonium polymethacrylate, sodium polyacrylate, sodium polymethacrylate, polyethyleneimine, dilute nitric acid, dilute hydrochloric acid, dilute sulfuric acid, and phosphoric acid. Specific examples of the dispersant include ammonium polyacrylate, ammonium polymethacrylate, dilute nitric acid, and dilute hydrochloric acid. Specific examples of the dispersant include at least one selected from the group consisting of ... dilute nitric acid and dilute hydrochloric acid.

[0083] The content of the dispersant is the mass of the dispersant relative to the total mass of the metal element, solvent, and dispersant in terms of oxide in the raw slurry, and can be, for example, 0.01 mass% or more or 0.05 mass% or more, and 10 mass% or less or 8 mass% or less.

[0084] The solid content concentration of the raw slurry can be, for example, 30% by mass or more, or 40% by mass or more, or 90% by mass or less, or 85% by mass or less. The solid content concentration of the raw slurry is the ratio [mass %] of the mass of metal elements in the raw slurry, calculated as oxides, to the mass of the raw slurry. For example, in the case of a raw slurry in which the matrix source is alumina, the additive source is silica, and the solvent is water, the solid content concentration can be calculated from {(mass [g] of silica + mass [g] of alumina) / (mass [g] of silica + mass [g] of alumina + mass [g] of water)} × 100. The solid content concentration can also be calculated as the mass ratio of the remainder after drying the solvent of the raw slurry to the mass of the raw slurry.

[0085] The raw slurry can be produced by any method as long as it involves mixing the matrix source and solvent, and further the matrix source, additive source, and solvent, but milling and mixing is preferred. A specific example of a method for producing the raw slurry is mixing the matrix source, additive source, and solvent, followed by ball milling. The grinding media used in the ball mill may be any medium capable of removing slow aggregation of the matrix source and additive source, such as ceramic balls with an average particle size larger than that of the matrix source, etc. Examples of such grinding media include ceramic balls with a diameter of 0.5 mm to 20 mm, and even 1 mm to 15 mm. Examples of ceramic balls include alumina balls and / or zirconia balls. To prevent impurities from being mixed in during grinding and mixing, alumina balls are preferred as the grinding media.

[0086] The mixing time can be varied depending on the amount of ceramic slurry required and the target particle size, and can be, for example, from 12 to 72 hours. The longer the mixing time, the smaller the average particle size tends to become until equilibrium is reached.

[0087] By adjusting the viscosity of the raw material slurry to an appropriate range, mixing efficiency improves and it becomes easier to obtain a slurry in which the matrix source and other components are uniformly dispersed in the solvent. Specific examples of the viscosity of the raw material slurry include a range of 50 mPa·s to 2000 mPa·s.

[0088] The fiber cloth may be similar to the fiber cloth contained in the target CMC of this embodiment, and is preferably a fiber cloth made of one or more types of ceramic continuous fibers selected from the group consisting of silicon carbide, alumina, mullite, zirconia, alumina and mullite, alumina and silica, and alumina, silica, and boron oxide, more preferably a fiber cloth made of one or more types of ceramic continuous fibers selected from the group consisting of alumina, mullite, alumina and mullite, and alumina and silica, and even more preferably a fiber cloth made of one or more types of ceramic continuous fibers selected from the group consisting of alumina, mullite, and alumina and mullite.

[0089] The fiber cloth in the manufacturing method of this embodiment is preferably a fiber cloth that has been subjected to a desizing treatment. The desizing treatment burns off organic matter and the like on the surface of the fiber cloth, making it easier for the raw material slurry and the fiber cloth to adhere to each other. The conditions for the desizing treatment include the following:

[0090] Desizing temperature: 800℃ Desizing time: 1 hour Desizing atmosphere: Air atmosphere The thickness of the fiber cloth after desizing is 0.05 mm or more, 0.08 mm or more, 0.10 mm or more, 0.12 mm or more, or 0.15 mm or more, and 0.40 mm or less, 0.35 mm or less, 0.30 mm or less, or 0.25 mm or less, such as 0.05 mm or more and 0.40 mm or less, 0.08 mm or more and 0.30 mm or less, 0.10 mm or more and 0.25 mm or less, or 0.10 mm or more and 0.20 mm or less.

[0091] The thickness of the fiber cloth may be determined by a method conforming to JIS L 1096 8.4A using a general thickness measuring device (for example, a digital thickness measuring device manufactured by Toyo Seiki Seisakusho, Ltd.) The thickness of the fiber cloth may be determined by averaging the values ​​obtained by measuring five points with a jig applied pressure of 23.5 kPa and a pressure holding time of 10 seconds.

[0092] The manufacturing method of this embodiment includes a step of solidifying the mixture to obtain a molded body (hereinafter also referred to as the "molding step"). This results in a molded body that serves as a precursor to the CMC of this embodiment. The molding method may be any method that allows the mixture to have a fixed shape, and examples include one or more methods selected from the group consisting of heat treatment, freezing treatment, and additive treatment. The molding step may involve a combination of the above methods, or the same treatment may be performed multiple times.

[0093] The heat treatment may be carried out under the following conditions.

[0094] Heat treatment temperature: 50°C or higher, 60°C or higher, or 80°C or higher, and 160℃ or less or 140℃ or less Number of heat treatments: 1 to 5 times The heat treatment time can be adjusted as desired depending on the amount of the mixture to be treated and the heat treatment temperature, and can be, for example, from 1 hour to 10 hours, or from 2 hours to 8 hours.

[0095] The freezing treatment may be carried out under the following conditions.

[0096] Freezing temperature: -200°C or higher or -180°C or higher, and -20℃ or below or -30℃ or below Sublimation pressure: 0.001 MPa or more or 0.002 MPa or more, and 0.05MPa or less or 0.03MPa or less Number of times of processing: 1 to 5 times When the freezing treatment is carried out multiple times, the freezing temperature and sublimation pressure may be set to any desired conditions.

[0097] The additive treatment includes a process of mixing an additive such as a solidifying agent or a binder with the mixture and molding the mixture. The additive may be any known additive that can be used in the production of CMC, such as agar, gelatin, methyl cellulose, camphene, sodium alginate, 2-hydroxyethyl acrylate, 4-hydroxybutyl acrylate, 6-hydroxyhexyl acrylate, acrylic acid, methacrylic acid, acrylamide, N,N'-methylenebisacrylamide, N,N'-ethylenebisacrylamide methacrylamide, polyethylene glycol diacrylate, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, urea, boron nitride (BN), aluminum nitride (AlN), silicon nitride (Si3N4), gallium nitride (GaN), zirconium nitride (ZrN), polyaluminum chloride ([Al2(OH) n Cl 6-n ] m , 1≦n≦5, m≦10), trimethoxyaluminum, triethoxyaluminum, tri-n-propoxyaluminum, tri-i-propoxyaluminum, tri-n-butoxyaluminum, tri-i-butoxyaluminum, tri-sec-butoxyaluminum, tri-t-butoxyaluminum, trimethoxyboron, triethoxyboron, tri-n-propoxyboron, tri-i-propoxyboron, tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane Examples include one or more selected from the group consisting of silane, tetra-i-propoxysilane, tetra-n-butoxysilane, tetra-i-butoxysilane, tetra-n-butoxysilane, tetra-sec-butoxysilane, tetra-t-butoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, paraffin wax, and polyvinyl alcohol.

[0098] The additive treatment is preferably one or more methods selected from the group consisting of a method of mixing a solidifying agent and a binder with the mixture, a method of mixing a solidifying agent with the mixture, and a method of mixing a binder with the mixture, and the method of mixing a solidifying agent and a binder with the mixture is more preferred.

[0099] The method for producing a CMC of this embodiment may include a step of calcining the molded body to obtain a calcined body (hereinafter also referred to as a "calcining step") prior to firing the molded body.

[0100] In the calcination step, the compact is calcined to obtain a calcined body. The calcination conditions may be any conditions that allow necking between the particles of the matrix source to proceed, and examples of the conditions include the following:

[0101] Calcination atmosphere: oxidizing atmosphere or inert atmosphere, preferably air atmosphere Calcination temperature: 800°C or higher or 850°C or higher, and Less than 1000℃ or 900℃ or less The calcination time may be changed as desired depending on the size of the molded body and the characteristics of the calcination furnace used, and may be, for example, from 30 minutes to 120 hours.

[0102] In the manufacturing method of this embodiment, the calcined body may further be subjected to a mixing step. The mixing step may be performed under the same conditions as those described above, except that the calcined body is used instead of the molded body. The calcined body after mixing with the raw material slurry may be calcined by any method.

[0103] When the method for producing a CMC of this embodiment includes a calcination step, a calcined body may be subjected to firing instead of a molded body.

[0104] The manufacturing method of this embodiment includes a step of firing the molded body (hereinafter also referred to as the "firing step"). This produces the CMC of this embodiment. When the manufacturing method of this embodiment includes a calcination step, a calcined body can be used for firing instead of the molded body. The firing can be performed under any conditions that allow sintering of the matrix source to proceed, and examples of the firing conditions include the following:

[0105] Firing atmosphere: oxidizing atmosphere or inert atmosphere, preferably air atmosphere Firing temperature: 1000°C or higher, 1100°C or higher, or 1200°C or higher, and 1500℃ or less, 1450℃ or less, or 1400℃ or less Number of firings: 1 to 5 The firing time may be varied as desired depending on the size of the compact (or calcined compact) and the characteristics of the firing furnace used, and may be, for example, from 30 minutes to 120 hours. When firing is performed multiple times, the firing atmosphere and firing temperature may be set as desired.

[0106] For ease of operation, atmospheric firing is preferred. In this embodiment, "atmospheric firing" refers to a method of firing by heating the object to be fired (such as a compact or a calcined body) without applying an external force. [Example]

[0107] The present disclosure will be described below with reference to examples, but the present disclosure is not limited to these examples.

[0108] (viscosity) The viscosity of the slurry was measured in accordance with the viscosity measurement method using a single cylinder rotational viscometer of JIS Z 8803 using a B-type rotational viscometer (device name: TVB-10 type viscometer, manufactured by Toki Sangyo Co., Ltd.) under the following conditions.

[0109] Rotation speed: 12 rpm SPINDLE No.: M2 Container: 500ml tall beaker (Average particle size) The average particle size was measured in accordance with JIS R 1629 using a laser diffraction / scattering particle size distribution analyzer (device name: MT3300EX-II, manufactured by Microtrackbell) under the following conditions.

[0110] Light source: Semiconductor laser Voltage: 780mW Refractive index of alumina: 1.77 Refractive index of zirconia: 2.17 Refractive index of silica: 1.48 Refractive index of solvent (water): 1.333 Calculation mode: MT3000EXII (BET specific surface area) The BET specific surface area was measured in accordance with JIS Z 8830 by the BET single-point method using nitrogen as the carrier gas as the adsorption gas, using a gas adsorption amount measuring device (device name: BELSORP MR6, manufactured by MICROTRAC) under the following conditions.

[0111] Adsorption medium: N2 Adsorption temperature: -196℃ Pretreatment conditions: Treatment in air at 200°C for 25 minutes (thickness of fiber cloth) The thickness was measured using a thickness measuring device (device name: digital thickness measuring device, manufactured by Toyo Seiki Seisakusho Co., Ltd.) according to the method of JIS L 1096 8.4A. The pressure applied by the jig was 23.5 kPa, the pressure was held for 10 seconds, and measurements were taken at five points. The average value of the values ​​obtained was taken as the thickness of the fiber cloth.

[0112] (fiber volume fraction) The fiber volume fraction was calculated using the following formula:

[0113] Fiber volume fraction [volume%] = (V f / V CMC ) x 100 V f = m / ρ f V CMC = A×B×t CMC In the above equation, V f is the volume of the ceramic continuous fiber cloth, V CMC is the volume of the CMC, m is the mass of the ceramic continuous fiber cloth [g], ρ f is the density of the ceramic continuous fiber cloth [g / cm 3 ], A is the length of the CMC [cm], B is the width of the CMC [cm], and t CMC is the thickness of the CMC [cm].

[0114] (Measured density) The measured density is the mass [g / cm ] measured using an electronic balance relative to the volume measured by the Archimedes method, according to JIS R 1634. 3 Prior to the measurement, the mass of the dried CMC was measured, and then the CMC was placed in water, boiled for 3 hours, and left to stand at room temperature for 6 hours or more as a pretreatment.

[0115] (CMC thickness) The thickness of the CMC was measured at three points using a micrometer, and the average value was taken as the CMC thickness.

[0116] (tensile strength) Tensile strength was measured using a strength testing machine (AG-XPlus, manufactured by Shimadzu Corporation) and a tensile test jig according to a method in accordance with JIS R 1656. Measurements were performed twice, and the average value was calculated. CMC samples were processed to a width of 10 ± 1 mm and a length of 110 ± 10 mm, and aluminum tabs were attached to both ends to form tensile test specimens. The width and thickness of the tensile test specimens were measured using a micrometer, and the length of the specimen was measured using a vernier caliper. The loading rate was 0.5 mm / min. When the CMC thickness was 1 mm or more, it was processed to a thickness of 1 mm or more and 3 mm or less. When the CMC thickness was less than 1 mm, no processing was performed in the thickness direction. [Preparation of CMC] Example 1 91 g of α-alumina powder (average particle size: 0.15 μm, BET specific surface area: 14 m 2 / g), 2.8 g of spherical silica powder (average particle size: 0.24 μm, BET specific surface area: 25 m) was added as an additive source. 2 / g) was added to obtain a mixed powder. 31 g of diluted nitric acid water (pH = 2) was mixed with the mixed powder, and the pH was then adjusted using the diluted nitric acid water (pH = 2) to obtain a raw material slurry with a pH of 4. Mixing was carried out by ball milling for 24 hours using 10 mm diameter alumina balls as the milling medium. The obtained raw material slurry had a solids concentration of 75 mass% and a viscosity of 241 mPa s.

[0117] A commercially available alumina continuous fiber cloth (product name: Nextel-610, manufactured by 3M; a ceramic continuous fiber cloth with an α-alumina crystal structure and an Al2O3 content of 99% by mass) was treated (desized) at 800°C in an air atmosphere. The thickness of the alumina continuous fiber cloth after desizing was 0.142 mm. One sheet of the fiber cloth was impregnated with the raw material slurry and then solidified by heat treatment twice at 120±10°C for 6±2 hours, yielding a molded product measuring 110 mm wide, 130 mm long, and 0.191 mm thick.

[0118] The compact was heat-treated in an air atmosphere at 900°C to form a calcined body. The calcined body was then heat-treated in an air atmosphere at 1100°C and cooled to room temperature. The temperature was then increased again and heat-treated in an air atmosphere at 1200°C to obtain the CMC of this example.

[0119] This example is a CMC containing one alumina continuous fiber cloth, with a CMC thickness of 0.191 mm and a measured density of 2.95 g / cm 3 It was.

[0120] Example 2 A molded body having a width of 110 mm, a length of 130 mm, and a thickness of 0.359 mm was obtained in the same manner as in Example 1, except that two sheets of commercially available alumina continuous fiber cloth were stacked and impregnated with the raw material slurry. Next, a CMC of this example was obtained in the same manner as in Example 1, except that the molded body was used.

[0121] This example is a CMC containing two alumina continuous fiber cloths, with a CMC thickness of 0.359 mm and a measured density of 2.88 g / cm 3 It was.

[0122] Example 3 91 g of α-alumina powder (average particle size: 0.15 μm, BET specific surface area: 14 m 2 / g), 0.94 g of spherical silica powder (average particle size: 0.24 μm, BET specific surface area: 25 m) was added as an additive source. 2 / g) and 1.9 g of 3YSZ powder (average particle size: 0.04 μm, BET specific surface area: 14 m 2 A mixed slurry of this example was obtained in the same manner as in Example 1, except that 1000 mg / g of cellulose acylate was added. The obtained raw material slurry had a solids concentration of 75 mass % and a viscosity of 302 mPa·s.

[0123] A commercially available γ-alumina and silica mixed continuous fiber cloth (product name: Alf, manufactured by Nitibi Co., Ltd.; ceramic continuous fiber having a crystal structure of γ-alumina and amorphous silica, and an Al2O3 content of 72 mass% and an SiO2 content of 28 mass%) was desized in the same manner as in Example 1. The thickness of the γ-alumina and silica mixed continuous fiber cloth after desizing was 0.284 mm. A molded body having a width of 110 mm, a length of 130 mm, and a thickness of 0.317 mm was obtained in the same manner as in Example 1, except that one sheet of the fiber cloth was used. Next, a CMC of this example was obtained in the same manner as in Example 1, except that this molded body was used.

[0124] This example is a CMC containing one sheet of γ-alumina and silica mixed continuous fiber cloth, with a CMC thickness of 0.317 mm and a measured density of 2.31 g / cm 3 It was.

[0125] Example 4 As a matrix source, 125 g of 3YSZ powder (average particle size: 0.04 μm, BET specific surface area: 14 m) was used instead of 91 g of α-alumina powder. 2 The raw material slurry of this example was obtained in the same manner as in Example 1, except that a 100% sintered body (110 mm wide x 130 mm long x 0.212 mm thick) was used and no additive source was added. The obtained raw material slurry had a solids concentration of 75 mass % and a viscosity of 94 mPa·s. A molded body having a width of 110 mm, a length of 130 mm, and a thickness of 0.212 mm was obtained in the same manner as in Example 1, except that the obtained raw material slurry was used. Next, the molded body was heat-treated in an air atmosphere at 900°C to form a calcined body. The calcined body was again heated and heat-treated in an air atmosphere at 1100°C to obtain the CMC of this example.

[0126] This example is a CMC containing one alumina continuous fiber cloth, with a CMC thickness of 0.212 mm and a measured density of 3.09 g / cm 3 It was.

[0127] (Comparative Example 1) 2.8 g of spherical silica powder (average particle size: 0.24 μm) was added as an additive source to 91 g of α-alumina powder (average particle size: 0.15 μm) to obtain a mixed powder. 31 g of diluted nitric acid water (pH = 2) was mixed with the mixed powder to obtain a raw material slurry. Mixing was carried out in a ball mill for 24 hours using 10 mm diameter alumina balls as a milling medium.

[0128] Commercially available alumina continuous fiber cloth (product name: Nextel-610, manufactured by 3M) was treated (desized) at 800°C in an air atmosphere. Five desized alumina continuous fiber cloths were stacked and immersed in the raw material slurry. The resulting mixture was then solidified by heat treatment twice at 120±10°C for 6±2 hours, yielding a compact measuring 110 mm wide x 130 mm long x 1.902 mm thick.

[0129] The compact was heat-treated in an air atmosphere at 900°C to form a calcined body. The calcined body was then heat-treated in an air atmosphere at 1100°C and cooled to room temperature. Thereafter, the temperature was raised again and heat-treated in an air atmosphere at 1200°C to obtain the CMC of this comparative example.

[0130] The CMC of this comparative example has a CMC thickness of 1.902 mm and an actual measured density of 2.82 g / cm 3 It was.

[0131] (Comparative Example 2) The CMC of this comparative example was obtained in the same manner as in Comparative Example 1, except that five sheets of commercially available γ-alumina and silica mixed continuous fiber cloth (product name: Alf, manufactured by Nitibi Co., Ltd.) were used.

[0132] The CMC of this comparative example has a CMC thickness of 1.126 mm and an actual measured density of 2.31 g / cm 3 It was.

[0133] Tables 1, 3, 4 and 6 show the evaluation results of Examples and Comparative Examples containing alumina continuous fiber cloth, and Tables 2 and 5 show the evaluation results of Examples and Comparative Examples containing γ-alumina and silica mixed continuous fiber cloth.

[0134] [Table 1]

[0135] [Table 2]

[0136] [Table 3]

[0137] [Table 4]

[0138] [Table 5]

[0139] [Table 6]

[0140] The fiber volume fractions of Examples 1 to 4 were all 35% or less, which were smaller than the fiber volume fractions of the Comparative Examples.

[0141] The CMC of the examples had a CMC thickness of less than 0.5 mm. Comparing Examples 1 and 3, it was confirmed that even if the number of ceramic continuous fiber cloths was the same, the CMC thickness differed depending on the type of fiber cloth used and the matrix composition, etc. The thicknesses of the fiber cloths used in Examples 1 and 3 were 0.142 mm and 0.284 mm, respectively, confirming that the CMC thickness was thinner when the thickness of the fiber cloth used was thinner.

[0142] As shown in Figure 1, it was confirmed that the CMC of Example 3 exhibited sufficient elasticity to prevent cracking when bent by hand. To confirm the degree of bending of the CMC, the CMC was cut into a size of 1 cm wide x 10 cm long, compressed in the long direction using a vernier caliper, and the length bent until a crack occurred was measured. The length of the CMC of Example 1 was 14.20 mm.

[0143] Comparing Example 2 with Comparative Example 1, it was confirmed that the CMC of Example 2, even though it had two layers of fiber cloth, exhibited the same tensile strength as the CMC of Comparative Example 1, which had five layers of fiber cloth laminated together.

[0144] Comparing Example 3 with Comparative Example 2, it was confirmed that the CMC of Example 3, even though it had only one fiber cloth, exhibited the same tensile strength as the CMC of Comparative Example 2, which had five fiber cloths laminated together.

Claims

1. A ceramic matrix composite material comprising a ceramic matrix and a ceramic continuous fiber cloth, the ceramic matrix composite having a fiber volume fraction of 35% or less and a thickness of less than 0.5 mm.

2. The ceramic matrix composite material according to claim 1 , comprising one to three sheets of the ceramic continuous fiber cloth.

3. 3. The ceramic matrix composite material according to claim 1, wherein the ceramic matrix is ​​at least one selected from the group consisting of alumina, mullite, silica, and zirconia.

4. 3. The ceramic matrix composite material according to claim 1, wherein the ceramic continuous fiber cloth is a ceramic continuous fiber cloth made of one or more ceramic continuous fibers selected from the group consisting of alumina, mullite, alumina and mullite, and alumina and silica.

5. The ceramic continuous fiber cloth has an α-alumina structure in its crystal structure, and ２ O ３ 3. The ceramic matrix composite material according to claim 1, which is a ceramic continuous fiber cloth having a content of 60% by mass or more and 100% by mass or less.

6. 3. A method for producing a ceramic matrix composite material according to claim 1, comprising the steps of: mixing a slurry having a pH of 2.0 or more and 7.5 or less, containing a ceramic matrix source, with a ceramic continuous fiber cloth to obtain a mixture; solidifying the mixture to obtain a molded body; and firing the molded body.

7. The method according to claim 6, wherein the viscosity of the slurry containing the ceramic matrix source is 50 mPa·s or more and 2000 mPa·s or less.

8. A component comprising the ceramic matrix composite material according to claim 1 or 2.

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