Method for manufacturing sisic member

Abstract

To provide an unconventional new SiSiC member.SOLUTION: An SiSiC member in which at least one long hole is provided is obtained by impregnating an SiC formed body 3 in which a carbon tube 5 is arranged with Si. It is preferable that the SiC formed body 3 has a U-shaped groove 4, a carbon tube 5 is arranged in the groove 4, the inside of the groove 4 and the upper part of the carbon tube 5 are filled with a filler 8 containing SiC particles, and the filler 8 is treated as a part of the SiC formed body 3. The SiC formed body 3 is preferably impregnated with C before impregnation with Si. After the C impregnation, the SiC formed body 3 is preferably dried.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a SiSiC component. [Background technology]

[0002] Conventionally, SiSiC members, which are composite materials containing silicon carbide (SiC) and silicon (Si), have been known (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2019 / 194137 Summary of the Invention [Problem to be solved by the invention]

[0004] SiSiC materials have excellent properties such as thermal conductivity, and are expected to be used in a variety of applications, and the development of new SiSiC materials is also desired. For example, even if you try to drill a long hole in a SiSiC material with an inner diameter of 2 mm or less and a length of 100 mm or more, the SiSiC material is so hard that the drill will bend and you will not be able to achieve this.Even when processing using a laser, it is not possible to reach a depth of 100 mm while maintaining an inner diameter of 2 mm or less.

[0005] The present invention has been made in view of the above points, and has an object to provide a novel SiSiC member that has not been available conventionally. [Means for solving the problem]

[0006] As a result of extensive research, the present inventors have found that the above object can be achieved by employing the following configuration, and have completed the present invention.

[0007] That is, the present invention provides the following [1] to [6]. [1] A SiSiC member having at least one elongated hole formed therein, the SiSiC member having a tubular region A which is a region on the outer periphery of the elongated hole, and an extra-tubular region B which is a region outside the tubular region A, wherein the content of elemental Si in volume % in the extra-tubular region B is greater than the content of elemental Si in volume % in the tubular region A. [2] The SiSiC member according to [1] above, wherein the ratio A / B of the diameter of the Si element in the tubular region A to the diameter of the Si element in the extra-tubular region B is less than 0.2. [3] A SiSiC member having at least one elongated hole formed therein, the SiSiC member having a tubular region A which is a region on the outer periphery of the elongated hole, and an extra-tubular region B which is a region outside the tubular region A, wherein the content of elemental Si in the tubular region A is 20% by volume or less, and the diameter of the elemental Si in the tubular region A is 10 μm or less. [4] The SiSiC member according to any one of the above [1] to [3], wherein the diameter of the slot is 0.1 to 2 mm, and the length of the slot is 100 to 450 mm. [5] The SiSiC member according to any one of the above [1] to [4], wherein the volume ratio Si / SiC of elemental Si to SiC in the outer region B is 20 / 80 to 40 / 60. [6] A heating device comprising the SiSiC member according to any one of [1] to [5] above and a rod-shaped member, wherein the rod-shaped member is inserted into the slot. [Effects of the Invention]

[0008] According to the present invention, a novel SiSiC member that has not been available before can be provided. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view showing a SiSiC member. [Figure 2] FIG. 2 is a cross-sectional view showing a SiC compact. [Figure 3] FIG. 3 is a cross-sectional view showing a state in which a carbon tube is placed in a groove of a SiC compact. [Figure 4]FIG. 4 is a cross-sectional view showing a state in which the grooves of the SiC compact are filled with a filler material. [Figure 5] FIG. 5 is a schematic cross-sectional view showing the state in which Si spouts exist in the elongated hole. [Figure 6] FIG. 6 is a cross-sectional view showing a SiSiC member having a bonding surface. DETAILED DESCRIPTION OF THE INVENTION

[0010] FIG. 1 is a perspective view showing a SiSiC member 1. As shown in FIG. The SiSiC member 1 is a composite material containing silicon (Si) and silicon carbide (SiC), and has, for example, a low coefficient of thermal expansion and excellent heat resistance, wear resistance, thermal conductivity, strength, and the like. Inside the SiSiC member 1, a slot 2 that is long in one direction is provided.

[0011] 1 shows only one slot 2, the SiSiC member 1 may have multiple slots 2. When multiple slots 2 are present, the slots 2 may be parallel to each other or may intersect with each other, and this is set appropriately depending on the application of the SiSiC member 1. The slot 2 may be bent. The slot 2 may have one end sealed, or may penetrate from one end to the other end of the SiSiC member 1. The slot 2 is appropriately set depending on the application of the SiSiC member 1.

[0012] The diameter of the slot is appropriately set depending on the application of the SiSiC member, but is, for example, 0.1 to 2 mm, preferably 0.2 to 1.6 mm, and more preferably 0.5 to 1.2 mm. The length of the slot is set appropriately depending on the application of the SiSiC member, but is, for example, 100 to 450 mm, preferably 120 to 400 mm, and more preferably 150 to 300 mm. The diameter and length of the long hole are based on the diameter and length of the carbon tube (see FIGS. 3 and 4) described later.

[0013] As shown in FIG. 1, the SiSiC member 1 has a tubular region A that is a region on the outer periphery of the slot 2, and an extra-tubular region B that is a region outside the tubular region A.

[0014] First Embodiment The content of elemental Si (unit: vol %) in the extra-tubular region B is greater than the content of elemental Si (unit: vol %) in the tubular region A. That is, the tubular region A and the extratubular region B can be distinguished from each other by the content (unit: vol %) of elemental Si. Specifically, the ratio (A / B) of the content of elemental Si (unit: volume %) in the tubular region A to the content of elemental Si (unit: volume %) in the extra-tubular region B is less than 1, preferably 0.5 or less, and more preferably 0.3 or less.

[0015] It is preferable that the diameter of the Si simple substance in the extra-tubular region B is larger than the diameter of the Si simple substance in the tubular region A. Specifically, the ratio (A / B) of the diameter of the Si simple substance in the tubular region A to the diameter of the Si simple substance in the extratubular region B is preferably less than 1, more preferably 0.5 or less, even more preferably 0.3 or less, and particularly preferably less than 0.2.

[0016] Second Embodiment The content of simple Si in the tubular region A is 20% by volume or less, and the diameter of the simple Si in the tubular region A is 10 μm or less. The content of simple Si in the tubular region A is preferably 17% by volume or less, and more preferably 14% by volume or less. The diameter of the Si simple substance in the tubular region A is preferably 8 μm or less, and more preferably 6 μm or less.

[0017] On the other hand, it is preferable that the content of simple Si in the outer tube region B exceeds 20% by volume and the diameter of the simple Si in the outer tube region B exceeds 10 μm. The content of simple substance Si in the outer region B is preferably 22% by volume or more, and more preferably 24% by volume or more. The diameter of the Si simple substance in the outer region B is preferably 12 μm or more, and more preferably 14 μm or more.

[0018] In any embodiment, the volume ratio of elemental Si to SiC (Si / SiC) in the outer region B is preferably 20 / 80 to 40 / 60, more preferably 22 / 78 to 30 / 70.

[0019] The contents (unit: volume %) of elemental Si and SiC, and the diameter of elemental Si are determined from optical microscope photographs as follows. In the micrograph of the cross section of a SiSiC component, the darkest part is pure C, the grey part that is lighter than pure C is SiC, and the lightest white part is pure Si. From a micrograph of an arbitrary cross section of a SiSiC member, the area ratios of elemental C, SiC, and elemental Si are calculated using image analysis software (WinROOF2015), and the calculated area ratios are used as the respective volume ratios. Additionally, the circle-equivalent diameter of each Si element is calculated and averaged to obtain the diameter of the Si element. In both cases, the average value obtained from any five fields of view is used.

[0020] In any embodiment, the thermal conductivity of the SiSiC member is preferably 180 W / (m·K) or more, and more preferably 200 W / (m·K) or more. The thermal conductivity is measured at room temperature (23°C) by the flash method using a xenon lamp light from a NETZSCH LFA447 (Nanoflash) lamp. More specifically, the thermal conductivity is measured over an area with a diameter of 25.4 mm, including the tubular region A of the SiSiC member at the center. The measurement thickness is 6 mm.

[0021] <Manufacturing method> A method for manufacturing a SiSiC member will be described with reference to FIGS.

[0022] <<Production of SiC compact>> FIG. 2 is a cross-sectional view showing the SiC compact 3. As shown in FIG. First, a SiC molded body 3 is formed. The SiC molded body 3 is a molded body containing SiC particles (not shown) and has a U-shaped groove 4. The shape of the groove 4 is not particularly limited as long as it is a shape that can fit a carbon tube 5 (see FIGS. 3 and 4) described later.

[0023] The SiC compact is also a porous body having many pores, and therefore, as will be described later, the SiC compact is impregnated with molten elemental Si. The porosity of the SiC compact is preferably 30 to 70% by volume, more preferably 40 to 60% by volume. The porosity is measured using a mercury porosimeter.

[0024] The dimensions and shape of the SiC compact are not particularly limited and are set appropriately depending on the dimensions and shape of the SiSiC member to be finally obtained.

[0025] To fabricate a SiC molded body, a 3D (three-dimensional) printing method such as laser irradiation molding or binder jet molding is used. In the 3D printing method, layers are formed one by one and stacked in order to obtain a SiC molded body, which is a laminated body of a desired shape. The thickness of each layer stacked in order is, for example, 0.2 to 0.3 mm.

[0026] In laser irradiation molding, a layer containing SiC particles and a binder is irradiated with a laser. The heat from the laser melts and solidifies the binder in the irradiated area, bonding the SiC particles together. This process is repeated for each layer that is stacked in sequence to create a SiC compact.

[0027] In binder jetting, a binder is sprayed from an inkjet nozzle onto a layer containing SiC particles. In the areas where the binder is sprayed, the SiC particles bond together. This process is repeated for each layer that is stacked in sequence to create a SiC compact. In binder jet molding, a layer containing SiC particles may contain a curing agent (e.g., an aqueous solution of an acidic substance containing xylene sulfonic acid, sulfuric acid, or the like) in advance, and the binder may react (cure) only in the area where the sprayed binder comes into contact with the curing agent. The content of the curing agent is, for example, 0.1 to 1 mass % relative to the SiC particles.

[0028] The SiC particles are preferably α-SiC. The average particle size of the SiC particles is, for example, 5 to 300 μm, preferably 30 to 200 μm, and more preferably 50 to 180 μm. Generally, the larger the SiC particles, the larger the pore size of the resulting SiC compact, so the average particle size of the SiC particles used can be appropriately selected depending on the desired pore size. The average particle size of the SiC particles is measured using a laser diffraction / scattering particle size distribution measuring device (MT3300EXII, manufactured by Microtrack Bell).

[0029] Examples of binders include thermosetting resins such as phenolic resins; self-hardening resins such as furan resins; and the like.

[0030] The SiC compact may be produced by 3D printing while forming the grooves. Alternatively, a SiC molded body without grooves may be first produced, and then grooves may be formed using a known cutting tool.

[0031] When producing a SiC compact without grooves, it is not necessary to use the 3D printing method. For example, a SiC compact may be produced by pouring a mixture of SiC particles and a binder (a SiC compact raw material) into a mold and drying it. The solid content of the SiC compact raw material may be varied appropriately within a range of, for example, 5 to 100 mass %. After drying, the SiC compact may be sintered by heating at a high temperature (for example, 1500 to 2300°C) in an inert atmosphere. An example of such a method is the method described in Japanese Patent Application Laid-Open No. 5-32458.

[0032] <<Carbon tube placement>> Next, as shown in FIG. 3, a carbon pipe 5 is placed in the groove 4 of the SiC compact 3. FIG. 3 is a cross-sectional view showing a state in which a carbon pipe 5 is placed in a groove 4 of a SiC compact 3. As shown in FIG. The carbon tube 5 is a tubular member having, for example, a plurality of carbon fibers 6 and a binder 7 such as an epoxy resin that fills the spaces between the carbon fibers 6. The carbon tube 5 becomes the tubular region A in the resulting SiSiC member 1 (see FIG. 1).

[0033] The carbon fiber content in the carbon pipe is, for example, 50 to 80% by volume, and preferably 55 to 75% by volume. The diameter of the carbon fiber is, for example, 2 to 10 μm, and preferably 4 to 8 μm.

[0034] When the carbon pipe is heated at a high temperature of, for example, 500°C or higher (specifically, when heated during the Si impregnation process described later), the binder volatilizes and the carbon pipe becomes porous, similar to the SiC compact. As a result, the carbon pipe is impregnated with molten Si, producing SiC, as described later.

[0035] The carbon pipe is not limited to a straight pipe, but may be bent. The carbon tube may be closed at one end, or a carbon tube with both ends open may be used, with one end filled with a filler material, as described below.

[0036] "filling" Next, as shown in FIG. 4, the inside of the groove 4 of the SiC compact 3 and above the carbon tube 5 is filled with a filler 8 containing SiC particles. FIG. 4 is a cross-sectional view showing a state in which grooves 4 of SiC compact 3 are filled with filler material 8. As shown in FIG.

[0037] For example, a mixture of SiC particles and a binder is placed in the grooves, and then the mixture is dried and heated, filling the grooves with a filler material having a composition similar to that of the SiC compact.

[0038] When using the binder jet molding method described above, for example, a mixture of SiC particles and a hardener is placed in the grooves, and then a binder is sprayed onto the mixture from an inkjet nozzle, filling the grooves with a filler material having the same composition as the SiC compact. At this time, if the grooves are deep, the grooves may be filled stepwise with the filler by repeatedly pouring in the mixture and injecting the binder.

[0039] Hereinafter, unless otherwise specified, the filler will be treated as part of the SiC compact.

[0040] <C Impregnation and drying> Next, optionally, the SiC compact may be impregnated with a dispersion in which carbon particles are dispersed (carbon dispersion), which will hereinafter also be referred to as "C impregnation." This allows the carbon particles to be introduced into the pores of the porous SiC compact. In this case, when the SiC compact is impregnated with Si as will be described later, part of the Si reacts with the carbon particles (C) to produce silicon carbide (SiC).

[0041] C impregnation is preferably carried out in a reduced pressure environment because this facilitates the introduction of carbon particles. After this, it is preferable to change the reduced pressure environment to a pressurized environment. This allows the carbon particles to be more easily introduced into the pores of the SiC compact. The content of carbon particles in the carbon dispersion is, for example, 20 to 60 mass %, and preferably 30 to 55 mass %. The average particle size of the aggregated particles (secondary particles) of the carbon particles is, for example, 100 to 200 nm, and preferably 110 to 150 nm. Examples of the dispersion medium for the carbon dispersion liquid include water; alcohols such as methanol and ethanol; and the like.

[0042] After the C impregnation, the SiC compact is preferably dried to remove the dispersion medium from the carbon dispersion liquid. Drying methods include natural drying, heat drying, and vacuum freeze drying. In the heat drying, the dispersion medium is removed by evaporation. When the dispersion medium is water, the heating temperature is, for example, 100 to 120°C. In the vacuum freeze-drying method, the dispersion medium is frozen by cooling in a drying chamber. The cooling temperature is a temperature below the freezing point of the dispersion medium, and when the dispersion medium contains water, it is, for example, −50 to −5° C. After freezing, the drying chamber is evacuated to a vacuum, whereby the dispersion medium is sublimated and removed.

[0043] <Si impregnation> Next, the SiC compact is impregnated with silicon (Si), which will hereinafter also be referred to as "Si impregnation." Specifically, for example, the SiC molded body and the elemental Si are brought into contact with each other and then heated to melt the elemental Si, which then impregnates the porous SiC molded body with the molten elemental Si due to capillary action. At this time, by melting the elemental Si while it is placed on the upper surface of the SiC molded body, the molten elemental Si can be more easily impregnated into the SiC molded body by utilizing gravity. The environment in which elemental silicon is melted is preferably a reduced pressure environment.

[0044] The heating temperature may be equal to or higher than the melting point of Si. The melting point of Si varies slightly depending on the measurement method, but is generally 1410 to 1414° C. The heating temperature is preferably 1500° C. or higher. On the other hand, the heating temperature is, for example, preferably 2300°C or lower, more preferably 2000°C or lower, and even more preferably 1650°C or lower.

[0045] Some of the Si impregnated into the SiC compact also reaches the carbon tube. As mentioned above, the carbon tube becomes porous when heated during the Si impregnation process. This introduces Si into the carbon tube. The Si then reacts with the carbon fibers (C) that make up the carbon tube, producing silicon carbide (SiC).

[0046] The Si that has been introduced into the SiC compact and that has not reacted with carbon (C) remains as is. Hereinafter, this Si will also be referred to as "free Si." In this way, a SiSiC component, which is a composite material containing SiC and free Si, is obtained. In the resulting SiSiC member, the region that was the carbon tube becomes a tubular region A (see FIG. 1), and the other region (SiC compact and filler) becomes an extra-tubular region B (see FIG. 1).

[0047] The amount of Si introduced into the SiC compact is appropriately set depending on the content of elemental Si in the SiSiC member finally obtained.

[0048] The resulting SiSiC member is sintered by the heat applied when melting the Si element. That is, SiC (including newly generated SiC) bonds with each other and with SiC, resulting in a dense sintered body. Therefore, the resulting SiSiC member is a composite material containing Si and SiC, and is also a sintered body.

[0049] <Si ejection> Here, the suppression of Si spout-out will be described with reference to FIG. FIG. 5 is a schematic cross-sectional view showing a state in which Si outflow 9 exists in slot 2. As shown in FIG.

[0050] The density of silicon (Si) in liquid state is 2.560 g / cm 3 whereas in the solid state it is 2.293 g / cm 3 is. In other words, when free Si is cooled from a heated molten state back to a solid state, its volume increases by 12% and it expands.

[0051] Therefore, as shown in FIG. 5, the free Si expands in volume, passes through the tubular region A, and can protrude into the slot 2 as a spout (Si spout 9). If a large Si outflow 9 exists in the slot 2 (the value of the Si outflow amount g in FIG. 5 is large), it is difficult (or impossible) to insert a rod-shaped member such as a thermocouple.

[0052] Incidentally, when carbon (C) reacts with silicon (Si) to form silicon carbide (SiC), the volume increases as shown in the following formula. C(52.1cm 3 ) + Si(96.8cm 3 ) → SiC(100.0cm 3 ) Therefore, in the tubular region A (carbon tube), when the introduced Si reacts with the carbon fiber (C) to generate SiC, volume expansion occurs, and a dense tubular wall is formed. As a result, even if the volume of free Si expands, it is difficult for the free Si to pass through the dense tubular region A. In this way, the ejection of Si is suppressed, and it becomes easier to insert a thermocouple or the like into the long hole. The amount of Si ejection g is preferably less than 1 mm, and more preferably less than 0.2 mm.

[0053] Since free Si does not easily pass through the tubular region A, the content of elemental Si (unit: volume %) in the extra-tubular region B of the resulting SiSiC component is greater than the content of elemental Si (unit: volume %) in the tubular region A, as described above. Moreover, the diameter of the Si simple substance in the extra-tubular region B is larger than the diameter of the Si simple substance in the tubular region A.

[0054] <Application> The use of the SiSiC member with slots is not particularly limited, but it can be used as a heating device due to its excellent thermal conductivity, strength, etc. For example, it is suitable as a top plate for a heating cooker such as an IH (induction heating) cooker. The top plate of the cooking device is a member on which an object to be heated, such as a pot, is placed. Ceramics and other materials have traditionally been used for top plates. However, top plates are required to be able to heat and cool quickly and have high impact resistance. For this reason, SiSiC materials are suitable for use as top plates for cooking appliances. For temperature control, a thermocouple (not shown) is inserted into a long hole in the SiSiC member, which allows the temperature of the SiSiC member and, by extension, the temperature of the object to be heated placed on the SiSiC member to be monitored.

[0055] The cooking appliance may be used as part of a system kitchen. A system kitchen has a work table, a cooking appliance, and other appliances connected by a worktop, which is made of materials such as stainless steel, artificial marble, and ceramics. The cooking device is used by being installed in an opening provided in a worktop, for example, and in this case, the top plate of the cooking device may form part of the worktop of the system kitchen.

[0056] Here, another embodiment of a SiSiC member having a slot, which is used in a cooking device, will be considered with reference to FIG.

[0057] FIG. 6 is a cross-sectional view showing a SiSiC member 21 having a bonding surface. First, in the same manner as described with reference to FIG. 2, an SiC molded body 3 having grooves 4 and an SiC molded body 3 without grooves are produced. 6, the SiC compact 3 without grooves is placed on the SiC compact 3 with grooves 4. At this time, the interface between the two is bonded using adhesive 22.

[0058] Consider a case where the SiSiC member 21 shown in Fig. 6 is used as a top plate of a cooking appliance. In this case, an object to be heated (not shown) is placed on the upper surface of the SiSiC member 21, and is heated from the lower surface. However, depending on the adhesive 22 used, heat may be blocked at the bonding surface, making it difficult for heat to be transferred to the object to be heated (i.e., poor thermal conductivity).

[0059] In contrast, the SiSiC member 1 (see FIG. 1) does not have such a bonding surface, and therefore it is relatively easy to heat an object to be heated, that is, it has good thermal conductivity.

[0060] The applications of the SiSiC member are not limited to the top plate of the above-mentioned cooking appliance, but also include heater members for electric furnaces used in heating experiments; members for semiconductor device manufacturing equipment; and the like. Depending on the application of the SiSiC member, the SiSiC member may be used with a rod-shaped member such as an electrode inserted into the long hole. [Example]

[0061] The present invention will be specifically described below with reference to examples, but the present invention is not limited to the examples described below. Below, Examples 1 and 2 are working examples, and Examples 3 and 4 are comparative examples.

[0062] Example 1 Groove-free SiC compacts were fabricated using a powder deposition 3D printer by binder jet molding. More specifically, a layer (approximately 0.2 mm thick) was formed using a mixture of SiC particles and a curing agent, and then a binder was sprayed onto the layer from an inkjet nozzle. This process was repeated to fabricate a rectangular SiC compact (300 mm x 300 mm x 20 mm). The SiC particles used were α-SiC powder (average particle size: 80 μm, manufactured by Shinano Electric Smelting Co., Ltd.). The curing agent used was a commercially available product manufactured by ASK Chemicals Japan Co., Ltd. (an acidic aqueous solution containing xylene sulfonic acid and sulfuric acid). The content of the curing agent in the mixture was 0.3 mass% relative to the SiC particles. The binder used was furan resin (manufactured by ASK Chemicals Japan Co., Ltd.).

[0063] Next, a milling machine was used to form grooves in the prepared SiC molded body without grooves, each groove having a shape into which a carbon tube, described below, could be fitted.

[0064] Next, a carbon tube (outer diameter: 1.5 mm, inner diameter: 0.7 mm, length: over 300 mm) was placed in the formed groove. Here, a carbon tube (carbon fiber diameter: 7 μm, carbon fiber content: 63 vol%, binder content: 37 vol%, manufactured by DPP) formed by solidifying multiple carbon fibers with a binder (epoxy resin) was used.

[0065] Next, the groove where the carbon tube was placed was filled with a filler containing SiC particles. More specifically, the mixture used for layer formation was mixed with the same binder as that sprayed from the inkjet nozzle, and this was placed in a groove (on top of a carbon tube) and then dried.

[0066] Next, C impregnation was carried out. That is, the SiC compact was immersed in a carbon dispersion liquid (carbon particle content: 40 mass%) in which carbon particles (average secondary particle diameter: 120 nm) were dispersed in water under a reduced pressure environment. In this way, the SiC compact was impregnated with the carbon dispersion liquid. The SiC molded body was then dried (vacuum freeze-dried). Specifically, the SiC molded body impregnated with the carbon dispersion was cooled at a temperature of −10 to 0° C. for 20 minutes in a drying chamber, and then the drying chamber was evacuated to vacuum. The content of carbon particles relative to SiC in the dried SiC molded body was measured using thermal analysis, and it was found to be 20 mass % in the region that would become the outer region B of the tube.

[0067] Next, Si impregnation was carried out. More specifically, first, Si elemental material (12.7 g) was placed on the SiC compact in a reactor. Next, the reactor was heated to 1550°C under a reduced pressure environment. This caused the Si elemental material to melt and impregnate the SiC compact, and some of it reached the carbon tube, generating SiC.

[0068] In this way, a SiSiC member, which is a sintered body containing free Si and SiC, was obtained.

[0069] Example 2 A SiSiC member was produced in the same manner as in Example 1, except that the C impregnation and subsequent drying were not carried out.

[0070] Example 3 First, a SiC molded body having a groove was produced in the same manner as in Example 1. Next, a carbon rod (diameter: 0.7 mm, length: more than 300 mm) was placed in the groove. Next, the groove after the carbon rod was placed was filled with a filler material and dried in the same manner as in Example 1. After the filler material hardened by drying, the carbon rod was pulled out to form a long hole (diameter: 0.7 mm, length: 300 mm). Thereafter, in the same manner as in Example 1, C impregnation, drying and Si impregnation were carried out to produce a SiSiC member.

[0071] Example 4 A SiSiC member was produced in the same manner as in Example 3, except that the C impregnation and subsequent drying were not carried out.

[0072] <evaluation> For the obtained SiSiC member, the content and diameter of elemental Si in the tubular region A and the extra-tubular region B were determined by the above-mentioned method. The results are shown in Table 1 below. In Examples 3 and 4, the region around the periphery of the elongated hole formed by drawing the carbon rod was designated as tubular region A, and the region outside tubular region A was designated as extratubular region B. Furthermore, the amount of Si blown out (g) (see Figure 5) was determined from a micrograph of the cross section of the obtained SiSiC member. The average value of five arbitrary fields of view was used as the amount of Si blown out (g). If the amount of Si blown out (g) was less than 0.2 mm, it was marked with "○", and if it was 0.2 mm or more, it was marked with "×" in Table 1 below. If the result was ○, it could be evaluated as having an excellent effect of suppressing Si blown out.

[0073] [Table 1]

[0074] <Summary of evaluation results> As shown in Table 1 above, in Examples 1 and 2, the content of simple Si (free Si) was higher in the extra-tubular region B than in the tubular region A. In Examples 1 and 2, the content of simple Si (free Si) in the tubular region A was 20% by volume or less, and the diameter was 10 μm or less. In Examples 1 and 2, the spouting of Si was suppressed.

[0075] On the other hand, Examples 3 and 4 did not satisfy any of these requirements.

[0076] Comparing Example 1 and Example 2, Example 1 (with C impregnation) had a lower content of simple Si in the outer region B and a smaller diameter of simple Si in the outer region B than Example 2 (without C impregnation). This is presumably because, in Example 1, which was impregnated with C, the impregnated molten Si reacted with C in the outer region B.

[0077] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design modifications are possible as long as they are within the scope of the claims. This application is based on Japanese Patent Application No. 2020-171499, filed on October 9, 2020, the contents of which are incorporated herein by reference. [Explanation of symbols]

[0078] 1: SiSiC material 2: Long hole 3:SiC molded body 4: Groove 5: Carbon pipe 6: Carbon fiber 7: Binder 8: Filling material 9:Si ejection 21: SiSiC material 22: Adhesive A: Tubular area B: Extrajudicial area g: Amount of silicon ejected

Claims

1. A method for manufacturing a SiSiC member, comprising: impregnating a SiC molded body having a carbon tube disposed therein with Si to obtain a SiSiC member having at least one elongated hole formed therein.

2. The SiC compact has a U-shaped groove, The carbon tube is placed in the groove; 2. The method for manufacturing a SiSiC member according to claim 1, wherein the inside of the groove and above the carbon tube are filled with a filler containing SiC particles, and the filler is treated as a part of the SiC compact.

3. The SiSiC member is a tubular region A that is an outer peripheral region of the long hole; an extratubular region B that is a region outside the tubular region A, The method for manufacturing a SiSiC member according to claim 2 , wherein the carbon tube forms the tubular region A, and the SiC compact and the filler form the extra-tubular region B.

4. 4. The method for producing a SiSiC member according to claim 3, wherein the content by volume of elemental Si in the extra-tubular region B is higher than the content by volume of elemental Si in the tubular region A.

5. The content of simple silicon in the tubular region A is 20% by volume or less, The method for producing a SiSiC member according to claim 3, wherein the diameter of the Si element in the tubular region A is 10 μm or less. However, the circle-equivalent diameter of each Si element is determined from an optical microscope photograph of an arbitrary cross section of the SiSiC member, and the average is used as the diameter of the Si element. The average value determined from any five visual fields is used.

6. The method for manufacturing a SiSiC member according to any one of claims 1 to 5, wherein the SiC compact is impregnated with C before the Si impregnation.

7. The method for producing a SiSiC member according to claim 6, wherein the SiC compact is dried after the C impregnation.

Images