Manufacturing method and manufacturing apparatus of ceramic base composite material

Abstract

To provide a manufacturing method and a manufacturing apparatus of a ceramic base composite material that are capable of forming an interface layer functioning as a barrier to a ceramic fiber, has a short work period, does not need a special installation, and enables lower cost.SOLUTION: A method has an interface layer formation process S1 and a matrix formation process S2. In the interface layer formation process, a treatment liquid permeation process, a heating process, a temperature holding process, and a cooling process are repeated several times until an interface layer 4 is formed on the whole ceramic fiber 1. In the treatment liquid permeation process, a treatment liquid 6 is penetrated to a ceramic fiber of a fabric preform 2. In the heating process, the treatment liquid penetrated in the fabric preform is heated to a first temperature T1 at which the film is boiled by a heat transfer from an induction heating body 10. In the temperature holding process, the whole fabric preform is covered by the film-boiled film between the induction heating bodies and the heat decomposition product 7 is precipitated to a fiber surface. In the cooling process, the fabric preform is cooled up to a second temperature T2 at which the treatment liquid is penetrated into an inside of the fabric preform.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method and an apparatus for producing a ceramic matrix composite material having an interface layer. [Background technology]

[0002] Ceramic matrix composites (CMC) are used as high-temperature structural components in rocket engines and aircraft jet engines. Ceramic matrix composites are materials that use ceramics as a matrix and reinforcement fibers within the matrix. Ceramic fibers, for example, are used as the reinforcement fibers.

[0003] In ceramic-based composite materials reinforced with ceramic fibers, cracks occur in the matrix, and the strength and fatigue properties decrease when the cracks cross the fibers. Therefore, an interface layer may be formed between the fiber and the matrix to increase the strength and extend the life of the CMC. The interface layer prevents the propagation of cracks in the matrix that cross the fibers by allowing them to propagate along the interface layer. Such an interface layer is disclosed in, for example, Patent Documents 1-3.

[0004] US Patent No. 5,399,633 describes a method for forming an interphase in a ceramic matrix composite having a plurality of SiC fibers, which includes selectively removing (e.g., etching) silicon from the surface of the fibers to provide a porous carbon layer on the fibers, and replacing the porous carbon layer with an interphase layer (e.g., boron nitride).

[0005] Patent Document 2 discloses a ceramic-based composite material in which the interface layer is composed of an inner layer formed by CVI, an intermediate layer made of particles of an antioxidant, and an outer layer formed by CVI.

[0006] Patent Document 3 discloses a method in which a hydrocarbon gas such as methane, ethane, or propane is supplied to a SiC or C fiber preform contained in a reactor, the hydrocarbon gas is thermally decomposed, and C, which is a thermal decomposition product, is precipitated around the SiC or C fiber.

[0007] On the other hand, the film boiling method (hereinafter referred to as the FB method) is known as a method for forming the matrix of CMC. The FB method is a method in which the matrix is ​​rapidly filled by immersing the substrate in a liquid raw material and heating it. The FB method is disclosed in, for example, Patent Documents 4 and 5.

[0008] The method of Patent Document 4 includes immersing a porous substrate in a liquid precursor, inductively heating the porous substrate at a first power level, and increasing the power level above the first power level when a densified region in the porous substrate approaches an outer surface of the porous substrate. When the power level is increased above the first power level, a barrier (e.g., a mesh material) is moved adjacent to the surface of the porous substrate to contact the liquid precursor with the porous substrate.

[0009] The matrix formation method of Patent Document 5 involves forming a matrix by heating reinforcing fibers placed in a liquid matrix raw material, and repeatedly increasing and decreasing the heating temperature so that the matrix structure becomes a layered structure in which multiple layers are stacked on top of each other. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] JP 2018-184695 A [Patent Document 2] JP 2003-321277 A [Patent Document 3] JP 2002-211985 A [Patent Document 4] JP 2010-255174 A [Patent Document 5] Patent Publication No. 2022-89297 Summary of the Invention [Problem to be solved by the invention]

[0011] In addition to the above-mentioned film boiling method (FB method), other conventional methods for forming a CMC matrix include chemical vapor deposition (hereinafter referred to as CVD method), chemical vapor infiltration (CVI method), polymer impregnation and firing (PIP method), and metal melt infiltration (MI method).

[0012] The CVD method is a method in which a source gas is supplied to the surface of a substrate and a thin film is formed by a chemical reaction. The CVI method is a method in which a source gas is supplied into the voids in a substrate and the matrix is ​​filled by a chemical reaction. The PIP method involves impregnating a substrate with a polymer that becomes carbon or SiC after pyrolysis, and then sintering it. The MI method is a method in which molten metal is impregnated into the inside of a substrate by capillary action.

[0013] Table 1 compares the five methods mentioned above. In this table, ◎ means very high superiority, ○ means high superiority, △ means low superiority, and × means very low superiority.

[0014] [Table 1]

[0015] As is clear from Table 1, all of the above five methods can form a matrix. On the other hand, it has been known that excellent interface layers can be formed by only three methods: CVD, CVI, and PIP.

[0016] However, when the CVD method or the CVI method is used for both the formation of the interface layer and the formation of the matrix, although it is possible to manufacture a CMC with excellent performance, there are problems in that the construction period is long (e.g., 300 to 500 hours or more), special equipment is required, and the cost is high. Furthermore, when the PIP method was used for both the formation of the interface layer and the formation of the matrix, there were problems such as insufficient performance and a long construction period.

[0017] On the other hand, the MI method can form a sufficiently excellent matrix and is also sufficiently cost-effective (low cost), but it is not suitable for forming the interface layer because the molten metal erodes the fibers. Therefore, when the MI method is applied to both the interface layer formation and matrix formation, there is a problem that the performance of the CMC is insufficient. In addition, the FB method can form a sufficiently excellent matrix, and the formation speed is very fast (about 50 times faster than the CVC method), so the cost of matrix formation is low. However, in the past, it was necessary to form the interface layer by either the CVD method, the CVI method, or the PIP method. Forming the interface layer by CVD or CVI results in high overall costs. In addition, when forming an interface layer using the PIP method, unlike matrix formation, repeated impregnation is not required, so the construction period is not long. However, it is difficult to apply the interface layer uniformly and to control the thickness. As a result, the performance of the interface layer is insufficient.

[0018] The method of Patent Document 4 mentioned above can densify a relatively small and thick porous substrate such as a friction brake disc, but since the porous substrate itself is heated inductively, it is difficult to uniformly heat a relatively large or thin porous substrate, and as a result, it is not possible to form a uniform interface layer that functions as a barrier over the entire ceramic fiber that constitutes the textile preform. In the method of Patent Document 4, even if the temperature environment is somewhat non-uniform or the accessibility of the raw materials varies depending on the location, and the growth rate is non-uniform at each position on the substrate, final densification is possible by, for example, extending the heating time or repeatedly heating the substrate. In this case, however, the construction period becomes longer in order to form a uniform interface layer.

[0019] Patent Document 5 is a matrix formation method, and discloses a CMC without an interface layer and a CMC in which the interface layer is formed by, for example, the method of Patent Document 2 (CVI method). In the case of a CMC without an interface layer, since there is no interface layer that functions as a barrier, it is not possible to prevent the progression of cracks that cross the fibers. In addition, when the interface layer is formed by the CVI method, there are problems with the CVI method, such as a long construction period, the need for special equipment, and high costs.

[0020] The present invention has been devised to solve the above-mentioned problems. That is, an object of the present invention is to provide a method and an apparatus for producing a ceramic matrix composite material, which can form an interface layer that functions as a barrier over the entire ceramic fiber, can be produced in a short period of time, does not require special equipment, and can reduce costs. [Means for solving the problem]

[0021] According to the present invention, there is provided a method for producing a ceramic-based composite material comprising a woven preform made of ceramic fibers, a matrix surrounding the ceramic fibers, and an interface layer located between the ceramic fibers and the matrix, the method comprising the steps of: (A) a treatment liquid permeation step of immersing the fabric preform and the induction heater in a treatment liquid containing a liquid precursor while the fabric preform is in close contact with one or both of induction heaters positioned at an interval, thereby permeating the treatment liquid into the ceramic fibers; (B) a heating step of inductively heating the induction heater in the liquid to a first temperature at which the treatment liquid that has permeated the textile preform undergoes film boiling by heat transfer from the induction heater; (C) a temperature holding step in which the first temperature is held, the fabric preform is covered with a film boiling film, and a thermal decomposition product of the treatment liquid is precipitated on a surface of the ceramic fiber; (D) a cooling step of stopping the induction heating and cooling the fabric preform to a second temperature at which the treatment liquid permeates into the fabric preform, The treatment liquid infiltrating step, the heating step, the temperature maintaining step, and the cooling step are repeated a number of times until the interface layer functioning as a barrier is formed over the entire ceramic fibers.

[0022] According to the present invention, there is also provided an apparatus for producing a ceramic-based composite material, the apparatus comprising: a woven preform made of ceramic fibers; a matrix surrounding the ceramic fibers; and an interface layer located between the ceramic fibers and the matrix, the apparatus comprising: an induction heater having an outer surface in close contact with the woven fabric preform and capable of induction heating; a preform holding device that holds the shape of the fabric preform in a state where the fabric preform is in close contact with the induction heater; a chamber capable of holding a processing liquid including a liquid precursor therein; an induction heating coil surrounding the chamber; an induction heating device that uses the induction heating coil to induction heat the induction heater located in the treatment liquid; A heating control device for controlling the induction heating device, The preform holding device is positioned opposite the induction heater with the woven fabric preform therebetween, and has a temperature equalizing member for equalizing the temperature of the woven fabric preform, thereby providing an apparatus for producing a ceramic-based composite material. Effect of the Invention

[0023] According to the manufacturing method of the present invention described above, in the heating step, the induction heating element is induction heated to the first temperature at which the treatment liquid that has permeated the textile preform undergoes film boiling by heat transfer from the induction heating element, so that a relatively large or thin textile preform can be heated evenly.

[0024] In addition, in the temperature holding process, the woven fabric preform is in close contact with one or both of the induction heaters positioned at a distance, so that the first temperature is held and the entire woven fabric preform is covered with a film boiling film between the induction heaters, and the pyrolysis products of the treatment liquid are precipitated on the surface of the ceramic fibers, forming a uniform interface layer that functions as a barrier.

[0025] Furthermore, since the method includes the cooling step of cooling the textile preform to the second temperature at which the treatment liquid permeates into the interior of the textile preform, the treatment liquid can be permeated again.

[0026] Therefore, by repeating the treatment liquid impregnation step, heating step, temperature holding step, and cooling step multiple times, an interface layer that functions as a barrier can be formed over the entire ceramic fiber.

[0027] Moreover, it was confirmed that an excellent CMC could be formed by the below-described Example in which a matrix was formed by the above-mentioned MI method after the formation of the interface layer according to the present invention.

[0028] Therefore, by combining the formation of the interface layer according to the present invention with the formation of a low-cost matrix, it is possible to produce a ceramic-based composite material that can be produced at low cost with a short production period and without the need for special equipment.

[0029] In addition, according to the manufacturing apparatus of the present invention, since it has a temperature equalizing member that equalizes the temperature of the textile preform at the first temperature at which the treatment liquid that has permeated the textile preform undergoes film boiling, it is possible to heat a relatively large or thin textile preform evenly. [Brief description of the drawings]

[0030] [Figure 1] FIG. 1 is an overall flow diagram showing a method for producing a ceramic-based composite material according to the present invention. [Diagram 2] FIG. 11 is an explanatory diagram of a temperature maintaining step S1-3. [Diagram 3]1 is an explanatory diagram of the repetition of a treatment liquid permeation step S1-1, a heating step S1-2, a temperature holding step S1-3, and a cooling step S1-4. [Figure 4] FIG. 4 is another view of FIG. 3(A). [Diagram 5] FIG. 1 is a comparison diagram between matrix formation and interface layer formation by the FB method. [Figure 6] FIG. 1 is a diagram showing a first embodiment of an apparatus for producing a ceramic-based composite material according to the present invention. [Figure 7] These are the temperature measurement results for "single treatment" and "triple treatment". [Figure 8] This shows an example in which an interface layer is formed by the method of the present invention, and then a matrix surrounding the interface layer is formed by the above-mentioned MI method. [Figure 9] FIG. 2 is a diagram showing a second embodiment of the apparatus for producing a ceramic-based composite material according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In addition, common parts in each drawing are given the same reference numerals, and duplicated explanations will be omitted.

[0032] FIG. 1 is an overall flow diagram showing a method for producing a ceramic-based composite material 50 according to the present invention. FIG. 2 is an explanatory diagram of the temperature maintaining step S1-3.

[0033] In the present invention, a ceramic matrix composite material 50 (CMC) comprises a woven preform 2 made of ceramic fibers 1, a matrix 3 surrounding the ceramic fibers 1, and an interface layer 4 located between the ceramic fibers 1 and the matrix 3.

[0034] In FIG. 1, the manufacturing method of the present invention includes an interface layer forming step S1 for forming an interface layer 4 (see FIG. 5), and a matrix forming step S2 for forming a matrix 3 (see FIG. 5). The interface layer forming step S1 includes a treatment liquid permeation step S1-1, a heating step S1-2, a temperature maintaining step S1-3, and a cooling step S1-4.

[0035] In the treatment liquid penetration step S1-1, with the textile preform 2 in close contact with the induction heater 10, the textile preform 2 and the induction heater 10 are submerged in a treatment liquid 6 containing a liquid precursor 5, and the treatment liquid 6 is penetrated into the ceramic fibers 1.

[0036] In the heating step S1-2, the induction heater 10 is induction-heated in the treatment liquid 6, and the treatment liquid 6 that has permeated the textile preform 2 is heated by heat transferred from the induction heater 10 to a first temperature T1 at which film boiling occurs.

[0037] In the temperature maintaining step S1-3, the first temperature T1 is maintained, the fabric preform 2 is covered with a film boiling film, and the pyrolysis product 7 of the treatment liquid 6 is precipitated on the surface of the ceramic fiber 1.

[0038] In the cooling step S1-4, the induction heating is stopped and the fabric preform 2 is cooled to a second temperature T2 at which the treatment liquid 6 permeates into the interior of the fabric preform 2.

[0039] In the interface layer forming process S1, the above-mentioned treatment liquid penetration process S1-1, heating process S1-2, temperature holding process S1-3, and cooling process S1-4 are repeated multiple times until an interface layer 4 functioning as a barrier is formed over the entire ceramic fiber 1. The number of repetitions is preferably two or more, and more preferably three or more.

[0040] The above-mentioned ceramic fiber 1 is, for example, a silicon carbide fiber, a carbon fiber, an alumina fiber, a mullite fiber, or a zirconia fiber. The liquid precursor 5 is, for example, an organic compound containing a hydrocarbon (for example, cyclohexane, toluene, xylene, benzene, pentane, etc.) or an organic compound containing boron (B) and nitrogen (N) (for example, borazine, aminoborane, diazaborane, triazaborane, etc.). The pyrolysis product 7 is carbon or boron nitride.

[0041] In FIG. 2, the woven fabric preform 2 has a thickness of, for example, about 4 mm, and is maintained in close contact with an induction heater 10, and in a treatment liquid permeation step S1-1, the ceramic fibers 1 are permeated with a treatment liquid 6.

[0042] In addition, in the heating process S1-2, a high-frequency current is passed through the induction heating coil 12 surrounding the induction heating body 10, thereby inductively heating the induction heating body 10 and heating the treatment liquid 6 that has permeated the textile preform 2 to a first temperature T1 at which film boiling occurs due to heat transfer from the induction heating body 10. The first temperature T1 is, for example, 800 to 1200°C, preferably 800°C to 1100°C.

[0043] Therefore, in the temperature holding step S1-3, the fabric preform 2 is held at the first temperature T1 at which the treatment liquid 6 undergoes film boiling, and the fabric preform 2 is covered with a film boiling film and the thermal decomposition products 7 of the treatment liquid 6 precipitate on the surfaces of the ceramic fibers 1. The holding time at the first temperature T1 in the temperature holding step S1-3 is preferably 50 to 60 minutes.

[0044] Particularly in the present invention, in the heating step S1-2, the textile preform 2 is heated to a first temperature T1 at which the treatment liquid 6 undergoes film boiling by heat transfer from the induction heater 10. Therefore, the temperature difference between the surface temperature of the induction heater 10 and the textile preform 2 is small, and has a gentle temperature gradient of, for example, 800°C to 1100°C.

[0045] In contrast, in the method of Patent Document 4, the porous substrate itself is induction heated, making it difficult to uniformly heat a relatively large or thin porous substrate. In addition, the liquid precursor is brought into contact with the porous substrate by moving a barrier (e.g., a mesh material) to the vicinity of the surface of the porous substrate, so that a part of the porous substrate is always in contact with the liquid precursor, and the temperature gradient (e.g., from 80°C to 1100°C) in the porous substrate is large. Therefore, with the method of Patent Document 4, it is difficult to form a thin film that is uniform in the thickness direction, and it is not possible to form a uniform interface layer 4 that functions as a barrier over the entire ceramic fibers that make up the woven preform.

[0046] FIG. 3 is an explanatory diagram of the repetition of a treatment liquid permeation step S1-1, a heating step S1-2, a temperature holding step S1-3, and a cooling step S1-4.

[0047] FIG. 3(A) shows the first heating step S1-2 and the first temperature holding step S1-3 following the treatment liquid penetration step S1-1. In the heating step S1-2, the induction heater 10 is induction heated to a first temperature T1 at which the treatment liquid 6 that has permeated the textile preform 2 undergoes film boiling by heat transfer from the induction heater 10, and the textile preform 2 located between the two induction heaters 10 becomes surrounded by a gas space generated by film boiling. In the first temperature holding step S1-3, regardless of the amount of the treatment liquid 6 that has permeated into the ceramic fiber 1 in the treatment liquid permeation step S1-1, the concentration in the gas space is higher near the gas-liquid exchange, so the thickness of the pyrolysis product 7 precipitated on the surface of the ceramic fiber 1 near the gas-liquid exchange is thick and the thickness is thin at locations away from the gas-liquid exchange. Furthermore, if the first temperature T1 is further increased in this state, the generation rate of the pyrolysis product 7 will increase, but this is not suitable for generating a uniform interface layer 4.

[0048] FIG. 3(B) shows the cooling state in the cooling step S1-4. When the induction heating is stopped and the textile preform 2 is cooled to the second temperature T2 at which the treatment liquid 6 permeates into the textile preform 2, the textile preform 2 becomes surrounded by the treatment liquid 6. As a result, the raw material concentration inside the textile preform 2 is restored, and the ceramic fibers 1 become permeated with the treatment liquid 6. At the end of the cooling step S1-4, the state becomes the same as that of the treatment liquid permeation step S1-1 described above.

[0049] FIG. 3(C) shows the second and subsequent heating steps S1-2 and temperature holding steps S1-3. In the heating step S1-2, as in the first heating step S1-2, the woven preform 2 becomes surrounded by a gas space generated by film boiling, and in the temperature holding step S1-3, as in the first temperature holding step S1-3, pyrolysis products 7 precipitate on the surface of the ceramic fiber 1.

[0050] In the present invention, in the interface layer formation process S1, the above-mentioned treatment liquid penetration process S1-1, heating process S1-2, temperature holding process S1-3, and cooling process S1-4 are repeated multiple times, so that an interface layer 4 that functions as a barrier can be formed over the entire ceramic fiber 1.

[0051] In the present invention, in the matrix formation step S2 in FIG. 1, the matrix 3 is formed after the above-mentioned interface layer 4 is formed.

[0052] FIG. 4 is a diagram showing another form of FIG. 3(A). As shown in FIG. 4(A), two fabric preforms 2 may be brought into close contact with one surface (upper surface or lower surface) of two induction heaters 10, respectively. In FIG. 6 of Example 1 described later, the first woven fabric preform 2 from the top has the configuration shown in FIG. 3(A), and the second and third woven fabric preforms 2 from the top have the configuration shown in FIG. Also, as shown in Fig. 4(B), a configuration may be used in which one woven fabric preform is used, the upper woven fabric preform is left, and the lower induction heater is replaced with an insulating plate. In this case, it is preferable that the distance between the insulating plate and the fiber preform is narrower than in the configuration of Fig. 4(A). This is the fourth woven fabric preform configuration from the top in Fig. 6.

[0053] 5 is a comparison diagram between the formation of a matrix by the FB method and the formation of an interface layer, in which (A) shows the formation of a matrix, and (B) shows the formation of an interface layer according to the present invention. As shown in FIG. 5(B), in the present invention, since it is necessary to trap the gas space, an environment closed above and below by two induction heaters is adopted. As shown in Fig. 5(A), the matrix formation by the FB method is similar. However, in normal matrix generation, both the top and bottom are not induction heated, and the side that is not in contact with the textile preform 2 is an insulating plate.

[0054] When generating the matrix in Figure 5(A), the temperature on the heating body (bottom surface of the preform) side was increased to precipitate matrix 3 from the heating body (bottom surface) side. This is because if dense matrix 3 is generated on the surface first, the raw material path will be blocked and voids will occur inside the preform, so it is necessary to generate it from the bottom surface. On the other hand, the interface layer formation in Figure 5(B) is aimed at forming a thin layer of a few μm around the fibers, rather than forming a dense matrix 3. Therefore, rather than gradually generating it from the bottom, it is necessary to carry out precipitation slowly and gradually throughout the entire preform. The temperature gradient is kept as gentle as possible, and induction heaters are installed above and below to gradually precipitate uniformly within the preform at a slightly lower temperature (= lower reaction rate) than the matrix formation.

[0055] In the formation of the interface layer in FIG. 5(B), there is a tendency for the interface layer to become thicker on the surface due to the effect of the concentration difference at the boundary in the gas-liquid exchange. However, in the present invention, this is offset by a gentle temperature gradient, and a uniform interface layer 4 is gradually deposited overall. EXAMPLES

[0056] FIG. 6 is a diagram showing a first embodiment of an apparatus for producing a ceramic-based composite material 50 according to the present invention. In this figure, the manufacturing apparatus of the present invention is an interface layer forming apparatus 20 that forms an interface layer 4, and in addition to the induction heating body 10 and induction heating coil 12 described above, has a chamber 13, an induction heating device 14, a heating control device 16, and a preform holding device 18.

[0057] The induction heater 10 is induction-heatable and has an outer surface that is in close contact with the textile preform 2. In this example, the induction heater 10 is two horizontal graphite plates 10a that are positioned horizontally and have an upper or lower surface that is in close contact with the textile preform 2. In this example, the horizontal graphite plates 10a are 90 mm in diameter and 20 mm thick.

[0058] In this example, the woven fabric preform 2 is an orthogonal three-dimensional woven fabric having dimensions of 70 mm×60 mm×2 mm, and the ceramic fibers 1 are made of Hi-Nicalon (registered trademark). Moreover, the four woven fabric preforms 2 are arranged in close contact with the upper and lower surfaces of the two horizontal graphite plates 10a, respectively, so that the interface layers 4 can be formed on the four woven fabric preforms 2 at the same time.

[0059] The chamber 13 is a container capable of holding therein a processing liquid 6 containing a liquid precursor 5 . In this example, the liquid precursor 5 is cyclohexane, which is dissolved in water to form the treatment liquid 6. The chamber 13 is made of heat-resistant glass.

[0060] The induction heating coil 12 is a conductive coil that spirally surrounds the outside of the chamber 13 . The induction heating device 14 applies a high-frequency current to the induction heating coil 12 , thereby inductively heating the induction heater 10 located in the treatment liquid 6 from outside the chamber 13 using the induction heating coil 12 . The heating control device 16 controls the induction heating device 14 .

[0061] The preform holding device 18 has a function of holding the shape of the fabric preform 2 in a state where the fabric preform 2 is in close contact with the induction heater 10 . In this example, the preform holding device 18 is suspended from above and held submerged in the processing liquid 6 in the chamber 13 .

[0062] In FIG. 6, the preform holding device 18 has a liquid supply plate 22, a preform holding mechanism 24, and a temperature equalizing member 30.

[0063] The liquid supply plate 22 has a liquid supply passage capable of supplying the treatment liquid 6 to the surface of the fabric preform 2 . In this example, the liquid supply plate 22 is a mesh plate 22, but it may be a porous body or woven fiber material capable of securing a gas path. In this example, the mesh plate 22 is a coarse-meshed wire netting in which two-dimensionally orthogonal vertical and horizontal wires overlap in the thickness direction at their intersections, and has a continuous liquid supply path that corresponds to the diameter of the wires in a two-dimensional manner. With this configuration, fluids (liquids and gases) can be communicated through the liquid supply path that is continuous from the outer edge to the center of the mesh plate 22. In this example, four mesh plates 22 are placed between two induction heaters 10, and one mesh plate is placed between each of two induction heaters 10 and two heat insulating plates 25.

[0064] The preform holding mechanism 24 is a pressure device 24 in this example, but may be any mechanism capable of holding the textile preform 2. In this example, the pressure device 24 applies a predetermined surface pressure to the fabric preform 2 via the heat insulating plate 25 in a state where the fabric preform 2 is sandwiched between the induction heater 10 and the mesh plate 22 .

[0065] In this example, a disk-shaped induction heater 10 and two disk-shaped insulating plates 25 having a diameter larger than that of the induction heater 10 were used. In addition, the two induction heaters 10 and the two insulating plates 25 were provided with circular openings at the same positions outside the woven fabric preform 2. Furthermore, the insulation plate 25, temperature equalizing member 30, mesh plate 22, woven fabric preform 2, and induction heater 10 were sandwiched between ceramic bolts 26a and ceramic nuts 26b that vertically penetrate the circular openings of the induction heater 10 and insulation plate 25, and surface pressure was applied. The applied surface pressure was set so that the shape of the fabric preform 2 could be maintained with the fabric preform 2 in close contact with the induction heater 10 in the state shown in the figure.

[0066] The temperature-uniformity member 30 is located opposite the induction heating body 10 with the woven fabric preform 2 sandwiched therebetween, and has a function of uniforming the temperature of the woven fabric preform 2. In this example, the temperature-uniformity member 30 is a first auxiliary heating plate 30A that is inductively heatable and is located between the upper mesh plate 22 and the insulating plate 25.

[0067] (heat cycle) The induction heating device 14 was controlled by the above-mentioned heating control device 16, and the heating process S1-2, temperature holding process S1-3, and cooling process S1-4 following the treatment liquid penetration process S1-1 were defined as one cycle (one time), and "one-time treatment" and "three-time treatment" were carried out.

[0068] (Temperature measurement results) Figure 7 shows the temperature measurement results for "one-time treatment" and "three-time treatment." In this figure, Figure 7(A) shows the temperature measurement results for one-time treatment, and Figure 7(B) shows the temperature measurement results for three-time treatment. In each figure, the horizontal axis represents time (min), the vertical axis represents temperature (° C.), and the numbers 1 to 4 in the figure represent the order of the woven fabric preform 2 from the top in FIG. Hereinafter, the woven fabric preform 2 with the reference numeral 1 will be referred to as "preform No. 1 2a," and the woven fabric preforms 2 with the reference numerals 2 to 4 will be referred to as preforms No. 2 to 4 2b, 2c, and 2d, respectively.

[0069] In FIG. 7(A), the sudden rise in temperature at about 60 minutes is due to an operational error resulting from the depletion of the processing solution.

[0070] Furthermore, in a preliminary test conducted under the same conditions as in Fig. 7(A) without the temperature-uniformizing member 30 in Fig. 6, the temperature of preform No. 1 2a was always lower than the others. This is thought to be because preform No. 2 2b and preform No. 3 2c are located between two induction heaters 10 and are heated on both sides, whereas preform No. 1 2a is only heated on its bottom by the single induction heater 10 located below. 6, in the present invention, a first auxiliary heating plate 30A capable of being inductively heated is provided between the mesh plate 22 on the upper side of the first preform 2a and the heat insulating plate 25. In this example, the first auxiliary heating plate 30A is a horizontal graphite plate that is thinner than the induction heating element 10.

[0071] In FIG. 7(A), the temperature of the first preform 2a has risen to about 900° C. due to the effect of the first auxiliary heating plate 30A. However, while the temperatures of the No. 2 preform 2b and the No. 3 preform 2c rose to approximately 1100°C, the maximum temperature of the No. 4 preform 2d was approximately 1000°C.

[0072] In FIG. 7(B), the maximum temperature of the No. 4 preform 2d was about 600° C. in the first step, about 750° C. in the second step, and about 800° C. in the third step, which were always lower than the others. This is thought to be because the second preform 2b and the third preform 2c are positioned between two induction heaters 10 and are heated on both sides, whereas the fourth preform 2d is heated on only one side by a single induction heater 10 positioned above. Therefore, it is preferable to provide a first auxiliary heating plate 30A capable of being induction heated also below the fourth preform 2d, similarly to the first preform 2a.

[0073] (Thickness of interface layer 4) Table 2 shows the film thickness of the interface layer 4 formed by the three-time treatment. The interface layer 4 is carbon or boron nitride (carbon in this example) having a layered structure in which multiple layers are stacked. The thickness of the interface layer 4 formed by the three-time treatment was 2.48 to 4.00 μm.

[0074] [Table 2] EXAMPLES

[0075] FIG. 8 shows an example in which an interface layer is formed by the method of the present invention, and then a matrix 3 surrounding the interface layer 4 is formed by metal infiltration (MI) method. In this example, a Si-Co alloy (Si-22 at. % Co, purity 99.9%) was used to form the matrix 3 at a vacuum degree of 10 Pa or less and an impregnation temperature of 1380°C.

[0076] In FIG. 8, the above-mentioned heating process S1-2, temperature holding process S1-3, and cooling process S1-4 constitute one cycle, and "one-time processing" refers to the case where the cycle is performed once, and "cycle (three-time) processing" refers to the case where the cycle is performed three times (three-time processing). Moreover, the upper images are SEM (backscattered electron image) images of the edge of the fabric (edge ​​of fabric preform 2) for the first and third treatments, and the lower images are SEM (backscattered electron image) images of the center of the fabric (center of fabric preform 2).

[0077] In each diagram in FIG. 8, the small gray circle is a cross section of the ceramic fiber 1 (SiC fiber in this example). The white blank area is the matrix 3 (SiCo alloy in this example). The black area surrounding the outer surface of the ceramic fiber 1 is the pyrolysis product 7 (carbon in this example) precipitated on the surface.

[0078] Comparing the results of one-time and three-time treatments in Figure 8, it can be seen that the thickness of the interface layer 4 is insufficient in the center of the one-time treatment, causing the fibers to be eroded by the molten metal. In contrast, in the case of the three-time treatment, an interface layer 4 of sufficient thickness is formed at both the ends and the center, and the interface layer 4 prevents the fibers (ceramic fibers 1) from being eroded by the molten metal.

[0079] (4-point bending test) Test pieces were prepared from parts of the specimens after melt impregnation, and four-point bending tests were carried out at room temperature and at elevated temperatures. As a result, the maximum bending stress was 604 MPa at room temperature and 619 MPa in Ar at 800°C. In addition, the material exhibited pseudo-ductile behavior in bending tests, and the tensile fracture strain at room temperature was 0.8% or more. EXAMPLES

[0080] Table 3 shows the results of strength measurements of the present invention, which uses the FB method as the interface formation method, and the comparative example, which uses the PIP method. Note that the matrix formation method in both cases is the MI method. From this table, it can be said that the CMC according to the present invention has a strength at least 40% higher than that of the comparative example in which the PIP method was used.

[0081] [Table 3]

[0082] From the above-mentioned examples, when the composite (matrix formation) was performed by the MI method which causes the most damage to the ceramic fibers 1, a CMC with higher strength was obtained by the method of the present invention than in the comparative example using the PIP method. Therefore, the method for producing the ceramic-based composite material 50 of the present invention is not limited to the compounding by the MI method, but can be said to be applicable to all other matrix formation methods. In addition, the combination of interface layer formation by the film boiling method (FB method) and matrix formation by the MI method in the above-mentioned embodiment has a very fast production speed, so that the manufacturing cost can be significantly reduced.

[0083] FIG. 9 is a diagram showing a second embodiment of an apparatus for producing a ceramic-based composite material 50 according to the present invention. In this figure, the manufacturing apparatus of the present invention is an interface layer forming apparatus 20 that forms an interface layer 4, and similarly to the second embodiment, has an induction heater 10, an induction heating coil 12, a chamber 13, an induction heating device 14, a heating control device 16, and a preform holding device 18.

[0084] In this example, the induction heater 10 is a graphite member having an outer circumferential surface surrounding a central axis ZZ. The central axis ZZ is a vertical axis in this example, but may be a horizontal axis or an inclined axis. When the woven fabric preform 2 is a flat body, the induction heater 10 is preferably a polygonal prism (for example, a quadrangular prism) whose outer circumferential surface is constituted by a flat surface wider than the woven fabric preform 2.

[0085] The induction heater 10 is not limited to this configuration, and may be a cylinder or a rotor whose outer circumferential surface changes in the axial direction. Furthermore, the induction heater 10 may be solid or hollow. In the case of a hollow heater, the thickness is not limited to a constant value, and may be variable so as to be able to heat uniformly. Furthermore, the induction heater 10 is not limited to being one unit, but may be separable.

[0086] In this example, the woven fabric preform 2 is made of ceramic fibers 1 that are wound around the outer circumferential surface of the induction heater 10 by filament winding or braid weaving while tension is applied to the ceramic fibers 1.

[0087] In this example, the preform holding device 18 also includes a flow path component 32 and a temperature equalizing member 30 . The flow path forming material 32 is, for example, a coarse wire mesh similar to the mesh plate 22 and has a function of fixing the fabric preform 2 to the induction heater 10 and a function of supplying the treatment liquid 6 to the surface of the fabric preform 2.

[0088] The temperature-uniformizing member 30 is an inductively heatable second auxiliary heating plate 30B located radially outside the induction heater 10 at a distance from the textile preform 2. The second auxiliary heating plate 30B may be, for example, a graphite plate. The temperature-uniformizing member 30 is preferably configured to be movable in the radial direction of the induction heater 10, and has a plurality of through-holes that penetrate in the radial direction. With this configuration, the treatment liquid 6 can be uniformly supplied in the radial direction to the entire surface of the textile preform 2 through the through holes of the temperature equalizing member 30 .

[0089] In this example, the preform holding device 18 is suspended from above and held submerged in the processing liquid 6 in the chamber 13, similarly to the first embodiment. The preform holding device 18 may be rotated about the central axis ZZ.

[0090] In FIG. 9, the interface layer forming device 20 further includes a plurality of partition plates 34 that divide the chamber 13 in the axial direction outside the temperature uniformizing member 30. The partition plates 34 are positioned at intervals in the axial direction of the induction heater 10 . The interface layer forming apparatus 20 further includes a plurality of processing liquid supply ports 36a and a plurality of processing liquid discharge ports 36b for supplying and discharging the processing liquid 6 to a plurality of regions (four in this example) separated by the partition plate 34, respectively. With this configuration, the treatment liquid 6 is supplied from the treatment liquid supply ports 36a provided in multiple regions and discharged from the treatment liquid discharge ports 36b, respectively, so that the treatment liquid 6 can be caused to flow in the diameter direction (horizontal direction) of the induction heating body 10 and evenly supplied to the surface of the woven fabric preform 2 through the through holes of the temperature-equalizing member 30.

[0091] In this example, the induction heating coil 12 is divided into four sections in the axial direction of the chamber 13, and the temperature of each section is controlled independently.

[0092] By using the above-mentioned interface layer forming device 20, even if the area of ​​the woven fabric preform 2 is large, the treatment liquid 6 can be supplied uniformly to the entire woven fabric preform 2, and the entire woven fabric preform 2 can be heated uniformly. Therefore, this configuration makes it possible to uniformize the thickness of the interface layer 4 of the woven fabric preform 2 having a large area, and also to reduce the manufacturing cost.

[0093] According to the embodiment of the present invention described above, in the heating step S1-2, the induction heater 10 is induction heated to the first temperature T1 at which the treatment liquid 6 permeated into the textile preform 2 undergoes film boiling by heat transfer from the induction heater 10. This allows the relatively large or thin textile preform 2 to be heated evenly.

[0094] Furthermore, in the temperature holding step S1-3, the woven fabric preform 2 is in close contact with one or both of the induction heaters 10 positioned at a distance, so that the first temperature T1 is held and the entire woven fabric preform 2 is covered with a film boiling film between the induction heaters 10, and the pyrolysis products 7 of the treatment liquid 6 are precipitated on the surfaces of the ceramic fibers 1, thereby forming a uniform interface layer 4 that functions as a barrier.

[0095] Furthermore, in the cooling step S1-4, the induction heating is stopped and the fabric preform 2 is cooled to the second temperature T2 at which the treatment liquid 6 permeates into the interior of the fabric preform 2, so that the treatment liquid 6 can be permeated again.

[0096] Therefore, by repeating the treatment liquid impregnation step S1-1, the heating step S1-2, the temperature holding step S1-3, and the cooling step S1-4 multiple times, the interface layer 4 that functions as a barrier can be formed over the entire ceramic fiber 1.

[0097] Furthermore, it was confirmed that in Examples 2 and 3 in which the matrix 3 was formed by the above-mentioned MI method after the formation of the interface layer 4 according to the present invention, a CMC excellent in four-point bending tests at room temperature and high temperature, tensile breaking strain at room temperature, and strength could be formed. Therefore, by combining the formation of the interface layer 4 according to the present invention with a relatively low-cost matrix formation method, it is possible to produce a ceramic matrix composite material 50 that can be produced at low cost with a short construction period and no need for special equipment.

[0098] Furthermore, the manufacturing apparatus of the present invention includes a temperature equalizing member 30 that equalizes the temperature of the textile preform 2 at the first temperature T1 at which the treatment liquid 6 that has permeated into the textile preform 2 by heat transfer from the induction heating body 10, caused by induction heating of the induction heating body 10, undergoes film boiling. This makes it possible to uniformly heat a relatively large or thin textile preform 2.

[0099] The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0100] T1 first temperature, T2 second temperature, 1 ceramic fiber, 2 woven preform, 2a first preform, 2b second preform, 2c third preform, 2d fourth preform, 3 matrix, 4 interface layer, 5 liquid precursor, 6 treatment liquid, 7 pyrolysis product, 10 induction heater, 10a horizontal graphite plate, 12 induction heating coil, 13 chamber, 14 induction heating device, 16 heating control device, 18 preform holding device, 20 interface layer forming device, 22 liquid supply plate (mesh plate), 24 preform holding mechanism (pressure device), 25 heat insulating plate, 26a ceramic bolt, 26b ceramic nut, 30 temperature uniforming member, 30A first auxiliary heating plate, 30B second auxiliary heating plate, 32 flow path component, 34 partition plate, 36a treatment liquid supply port, 36b treatment liquid discharge port, 50 Ceramic Matrix Composites (CMC)

Claims

1. A method for producing a ceramic matrix composite material comprising: a woven preform made of ceramic fibers; a matrix surrounding the ceramic fibers; and an interface layer located between the ceramic fibers and the matrix, the method comprising the steps of: (A) a treatment liquid permeation step of immersing the fabric preform and the induction heater in a treatment liquid containing a liquid precursor while the fabric preform is in close contact with one or both of induction heaters positioned at a distance from each other, thereby permeating the treatment liquid into the ceramic fibers; (B) a heating step of inductively heating the induction heater in the liquid to a first temperature at which the treatment liquid that has permeated the textile preform undergoes film boiling by heat transfer from the induction heater; (C) a temperature holding step in which the first temperature is held, the fabric preform is covered with a film boiling film, and a thermal decomposition product of the treatment liquid is precipitated on a surface of the ceramic fiber; (D) a cooling step of stopping the induction heating and cooling the fabric preform to a second temperature at which the treatment liquid permeates into the fabric preform, the treatment liquid infiltrating step, the heating step, the temperature maintaining step, and the cooling step are repeated a number of times until the interface layer functioning as a barrier is formed over the entire ceramic fiber.

2. The first temperature in the heating step is 800 to 1200° C., The second temperature in the cooling step is 100° C. or less, 2. The method for producing a ceramic-based composite material according to claim 1, wherein the treatment liquid permeation step, the heating step, the temperature holding step, and the cooling step are repeated two or more times.

3. 2. The method for producing a ceramic-based composite material according to claim 1, wherein the ceramic fibers are silicon carbide fibers, carbon fibers, alumina fibers, mullite fibers, or zirconia fibers.

4. 2. The method for producing a ceramic-based composite material according to claim 1, wherein the liquid precursor is an organic compound containing a hydrocarbon or an organic compound containing boron and nitrogen.

5. 5. The method for producing a ceramic-based composite material according to claim 4, wherein the organic compound containing a hydrocarbon is cyclohexane, toluene, xylene, benzene, or pentane.

6. 5. The method for producing a ceramic-based composite material according to claim 4, wherein the organic compound containing boron and nitrogen is borazine, aminoborane, diazaborane, or triazaborane.

7. 2. The method for producing a ceramic matrix composite material according to claim 1, wherein the pyrolysis product is carbon or boron nitride.

8. The method for producing a ceramic-based composite material according to claim 1 , wherein the interface layer is made of carbon or boron nitride having a layered structure in which a plurality of layers are stacked.

9. The method for producing a ceramic-based composite material according to claim 1 , wherein the matrix is ​​formed after the interface layer is formed.

10. An apparatus for producing a ceramic-based composite material, comprising: a woven preform made of ceramic fibers; a matrix surrounding the ceramic fibers; and an interface layer located between the ceramic fibers and the matrix, an induction heater having an outer surface in close contact with the woven fabric preform and capable of induction heating; a preform holding device that holds the shape of the fabric preform in a state where the fabric preform is in close contact with the induction heater; a chamber capable of holding a processing liquid including a liquid precursor therein; an induction heating coil surrounding the chamber; an induction heating device that uses the induction heating coil to induction heat the induction heater located in the treatment liquid; A heating control device for controlling the induction heating device, The preform holding device is positioned opposite the induction heater with the woven fabric preform sandwiched therebetween, and has a temperature equalizing member for equalizing the temperature of the woven fabric preform.

11. The induction heater is a horizontal graphite plate having an upper surface or a lower surface that is in close contact with the textile preform, The preform holding device comprises: a liquid supply plate having a liquid supply path capable of supplying the treatment liquid to the surface of the textile preform; a preform holding mechanism that holds the fabric preform via an insulating plate in a state where the fabric preform is sandwiched between the induction heater and the liquid supply plate, 11. The apparatus for producing a ceramic-based composite material according to claim 10, wherein the temperature-uniformizing member is a first auxiliary heating plate that is inductively heatable and is located between the liquid supply plate and the heat insulating plate.

12. The induction heater is a graphite member having an outer circumferential surface surrounding a central axis, the woven fabric preform is made of the ceramic fiber wound around an outer circumferential surface of the induction heater, The preform holding device comprises: A flow path component having a liquid supply path capable of supplying the treatment liquid to a surface of the textile preform, and the temperature equalizing member, 11. The apparatus for producing a ceramic-based composite material according to claim 10, wherein the temperature-uniformizing member is an inductively heatable second auxiliary heating plate located radially outward of the induction heating body at a distance from the woven fabric preform.

13. a plurality of partition plates positioned at intervals in the axial direction of the induction heater outside the temperature-uniformizing member and dividing the chamber in the axial direction; 13. The apparatus for producing a ceramic-based composite material according to claim 12, further comprising a plurality of treatment liquid supply ports and a plurality of treatment liquid discharge ports for supplying and discharging the treatment liquid to and from the plurality of regions separated by the partition plate, respectively.

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