Manufacturing method for Si-SiC composite structure

Abstract

To provide a production method of Si-SiC-based composite structure, capable of suppressing deformation of a compact, and manufacturing Si-SiC-based composite structure having a desired shape.SOLUTION: In a production method of Si-SiC-based composite structure in an embodiment, a compact containing SiC is brought into contact with a deformation suppression member for suppressing deformation of the compact, and in the state where a donor containing Si is brought into contact with the compact, the donor is heated, and a molten metal containing Si is impregnated into the compact.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for producing a Si-SiC composite structure. [Background technology]

[0002] Si-SiC composite materials have excellent thermal conductivity and are expected to be used in various industrial products. As a method for producing a structure formed from such a Si-SiC composite material (hereinafter referred to as a Si-SiC composite structure), for example, a technique has been proposed in which an impregnation metal supply body containing Si is heated to 1200°C or higher and 1600°C or lower while being in contact with an impregnated body containing SiC, and the body is impregnated with molten metal containing Si (see Patent Document 1).

[0003] It is desirable to manufacture such Si-SiC composite structures in shapes appropriate for their applications. Because the shape of the Si-SiC composite structure depends on the shape of the body to be impregnated, bodies of various shapes are heated as described above while in contact with the impregnation metal supplier. In this case, the body to be impregnated may deform due to its own weight and / or the load from the impregnation metal supplier, making it impossible to manufacture a Si-SiC composite structure with the desired shape. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2011 / 145387 Summary of the Invention [Problem to be solved by the invention]

[0005] A primary object of the present invention is to provide a method for producing a Si-SiC composite structure that can suppress deformation of a compact and that can produce a Si-SiC composite structure having a desired shape. [Means for solving the problem]

[0006] A method for manufacturing a Si-SiC composite structure according to an embodiment of the present invention includes the steps of bringing a molded body containing SiC into contact with a deformation suppression member for suppressing deformation of the molded body, and heating a supply body containing Si while the supply body is in contact with the molded body, and impregnating the molded body with molten metal containing Si. In one embodiment, the deformation suppression member is a support base having a support surface that conforms to the outer shape of the molded body, and the molten metal is impregnated into the molded body while the molded body is placed on the support base. In one embodiment, when the molded body is placed on the cradle, the support surface covers 30% or more of the outer surface of the molded body. In one embodiment, the molded body has a cylindrical shape. In one embodiment, the molded body is placed on the cradle so that the axis of the molded body is parallel to the horizontal direction. In one embodiment, the support surface has an arcuate shape, and the radius of curvature of the support surface is equal to or greater than half the outer diameter of the molded body and equal to or less than half the outer diameter of the molded body + 0.3 mm. In one embodiment, the supply body is disposed inside the molded body. In one embodiment, the support surface is provided with a coating layer. In one embodiment, the support surface is provided with a groove, which forms a gap between the molded body and the cradle when the molded body is placed on the cradle. In one embodiment, the receiving stand includes a first base having a first surface and a second base having a second surface. The molded body is placed on the first base and the second base. The first and second surfaces function as the support surfaces when the molded body is placed on the first and second bases. In one embodiment, the deformation suppression member has a first contact portion that contacts the molded body and a second contact portion that is located away from the first contact portion in a direction perpendicular to the longitudinal direction of the molded body and contacts the molded body. In one embodiment, the deformation suppressing member can suppress deformation of the plurality of molded bodies, which are arranged in a direction perpendicular to the longitudinal direction of the molded bodies and are in contact with one another. The deformation suppressing member has a first contact portion that contacts a molded body located at one end of the plurality of molded bodies, and a second contact portion that is located on the opposite side of the plurality of molded bodies from the first contact portion and that contacts a molded body located at the other end of the plurality of molded bodies. In one embodiment, the first contact portion and the second contact portion contact the molded body in a horizontal direction. In one embodiment, the deformation suppressing member further includes a third contact portion that contacts the molded body in a vertical direction. In one embodiment, the deformation suppressing member contains at least one material selected from carbon, boron nitride, alumina, and platinum. In one embodiment, the molded body has a honeycomb structure. [Effects of the Invention]

[0007] According to the embodiments of the present invention, deformation of the compact can be suppressed, and an Si—SiC based composite structure having a desired shape can be manufactured. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic perspective view for explaining a method for manufacturing a Si—SiC composite structure according to one embodiment of the present invention. [Figure 2] FIG. 2 is a front view of a cradle according to one embodiment of the present invention. [Figure 3] FIG. 3 is a front view of a cradle according to another embodiment of the present invention. [Figure 4] FIG. 4 is a front view of a cradle according to yet another embodiment of the present invention. [Figure 5]Fig. 5(a) is a front view of a cradle according to yet another embodiment of the present invention. Fig. 5(b) shows an embodiment in which the cradle shown in Fig. 5(a) is composed of a first unit and a second unit. Fig. 5(c) shows an embodiment in which the cradle shown in Fig. 5(a) has a groove. [Figure 6] Fig. 6(a) is a front view of a cradle according to yet another embodiment of the present invention. Fig. 6(b) shows an embodiment in which the cradle shown in Fig. 6(a) is composed of a first unit and a second unit. Fig. 6(c) shows an embodiment in which the cradle shown in Fig. 6(a) has a groove. [Figure 7] FIG. 7 is a front view of a honeycomb formed body according to one embodiment of the present invention. [Figure 8] FIG. 8 shows a state in which a molded body is contained in a container according to one embodiment of the present invention. [Figure 9] FIG. 9 shows a state in which a molded body is accommodated in a container according to another embodiment of the present invention. [Figure 10] FIG. 10 shows a state in which a plurality of molded bodies are accommodated in a container according to yet another embodiment of the present invention. [Figure 11] FIG. 11 shows a state in which a molded body is clamped by a clamping tool according to one embodiment of the present invention. [Figure 12] FIG. 12 shows a state in which an insertion jig according to one embodiment of the present invention is inserted into a molded body. [Figure 13] FIG. 13 shows a state in which an insertion jig according to another embodiment of the present invention is inserted into a molded body. [Figure 14] FIG. 14 shows a state in which an insertion jig according to still another embodiment of the present invention is inserted into a molded body. [Figure 15] FIG. 15 shows a state in which an insertion jig according to still another embodiment of the present invention is inserted into a molded body. [Figure 16] FIG. 16 shows a state in which an insertion jig according to yet another embodiment of the present invention is inserted into a molded body. [Figure 17] Figure 17(a) shows a state in which a molded body is supported by a support according to one embodiment of the present invention, and Figure 17(b) is a side view of the support shown in Figure 17(a). DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to these embodiments.

[0010] A. Overview of manufacturing methods for Si-SiC composite structures FIG. 1 is a schematic perspective view illustrating a method for manufacturing a Si—SiC composite structure according to one embodiment of the present invention; FIG. 2 is a front view of a support according to one embodiment of the present invention. A method for manufacturing a Si-SiC composite structure according to one embodiment of the present invention includes a step (impregnation step) of contacting a molded body 1 containing SiC with a deformation suppression member for suppressing deformation of the molded body, and contacting a supply body 3 containing Si with the molded body 1, and heating the supply body 3 to impregnate the molded body 1 with molten metal containing Si. According to this method, since the compact is in contact with the deformation suppressing member, deformation of the compact can be suppressed even when the supply body is heated and the molten metal is impregnated into the compact, and therefore, a Si-SiC composite structure having a desired shape can be produced.

[0011] In one embodiment, the deformation suppressing member is a pedestal 2 having a support surface 21 that conforms to the outer shape of the compact 1. In this case, the compact 1 is impregnated with molten metal containing Si while the compact 1 is placed on the pedestal 2. Because the support surface supports the compact along the outer shape while the compact is placed on the pedestal 2, deformation of the compact can be stably suppressed during the impregnation step.

[0012] When the molded body 1 is placed on the receiving stand 2, the support surface 21 preferably covers 30% or more, and more preferably 40% or more, of the outer surface of the molded body 1. If the support surface covers the outer surface of the molded body in this manner, deformation of the molded body during the impregnation process can be stably suppressed. Furthermore, the upper limit of the range of the outer surface of the molded body 1 covered by the support surface 21 is, for example, 100% or less, preferably 80% or less, and more preferably 50% or less. If the proportion of the outer surface of the molded body covered by the support surface is 50% or less, the molded body can be smoothly placed on the receiving stand. Note that when the molded body 1 is placed on the receiving stand 2, the support surface 21 covering the outer surface of the molded body 1 is in contact with the outer surface of the molded body 1, more specifically, in contact with the above-mentioned range of the outer surface of the molded body 1. The support surface 21 may entirely cover the molded body 1, or may include a portion that does not cover the molded body 1. In other words, the support surface 21 may entirely contact the molded body 1, or may include a portion that does not contact the molded body 1.

[0013] The molded body 1 may have any suitable shape depending on the application of the Si-SiC composite structure. Examples of the shape of the molded body include a columnar shape extending in a predetermined direction, specifically a circular cylinder, an elliptical cylinder, and a rectangular cylinder. Furthermore, the molded body may have a hollow region at the center in a cross section perpendicular to the axial direction (length direction). That is, the molded body may have a tubular shape (specifically, a cylindrical, elliptical, or rectangular cylinder).

[0014] In one embodiment, the molded body 1 has a cylindrical shape. In this case, the support surface 21 of the cradle 2 is an arcuate surface 22 having an arcuate shape. The arcuate surface 22 is recessed downward from the upper surface of the cradle 2 in a substantially C-shape. When the molded body 1 is placed on the cradle 2, the arcuate surface 22 (support surface 21) follows the outer peripheral surface of the molded body 1 and typically covers the above-mentioned range of the outer peripheral surface of the molded body 1. The radius of curvature of the arcuate surface 22 is, for example, at least 1 / 2 of the outer diameter of the cylindrical molded body 1, preferably at least 1 / 2 of the outer diameter of the molded body 1 + 0.03 mm, and for example, not more than 1 / 2 of the outer diameter of the molded body 1 + 0.3 mm, preferably not more than 1 / 2 of the outer diameter of the molded body 1 + 0.15 mm. If the radius of curvature of the arcuate surface is not less than the above-mentioned lower limit, the molded body can be smoothly placed on the receiving stand, and damage to the end of the arcuate surface due to contact with the molded body can be suppressed. If the radius of curvature of the arcuate surface is not more than the above-mentioned upper limit, the support surface can stably support the molded body when it is placed on the receiving stand.

[0015] In one embodiment, the compact 1 is placed vertically above the cradle 2. This method allows the cradle to more stably support the compact during the impregnation step. Furthermore, when the compact 1 has a columnar or tubular shape (typically a cylindrical shape) extending in a predetermined direction, the compact 1 is preferably placed on the cradle 2 so that the axis of the compact 1 is parallel to the horizontal direction. This can improve the packing efficiency of the compacts when multiple compacts are subjected to the impregnation step at once, thereby improving the production efficiency of Si-SiC composite structures. As shown in FIG. 1, the support surface 21 typically extends across the entire cradle 2 in a predetermined direction (the width direction of the cradle in FIG. 1). Furthermore, a plurality of molded bodies 1 may be placed on one support surface 21. The dimension of the support surface 21 in the extending direction (axial direction) is, for example, 0.8 times or more, preferably 1.1 times or more, the axial dimension of the molded body 1. If the longitudinal dimension of the support surface is equal to or greater than the above-mentioned lower limit, the molded body can be supported more stably. In particular, if the support surface has a length 2.1 times or more the length of the molded body, multiple molded bodies can be arranged on one support surface. In Fig. 1, one support surface 21 supports multiple (two) molded bodies 1, and the multiple (two) molded bodies 1 are lined up with a small gap in the extension direction of the support surface 21. The receiving table 2 may also have a plurality of support surfaces 21. In this case, the plurality of support surfaces 21 are arranged at intervals from one another in a direction intersecting (preferably perpendicular to) the direction in which the support surfaces 21 extend. This can further improve the packing efficiency of the plurality of compacts in the impregnation step.

[0016] The configuration of the receiving stand 2 is not particularly limited as long as it can support the molded body 1 as described above during the impregnation step. Fig. 3 is a front view of a receiving stand according to another embodiment (an embodiment including a first stand and a second stand); Fig. 4 is a front view of a receiving stand according to yet another embodiment (an embodiment in which the support surface has a groove). The receiving table 2 shown in FIG. 3 includes a first table 2a having a first surface 21a and a second table 2b having a second surface 21b. In the impregnation process, the compact 1 is placed on the first table 2a and the second table 2b. The first surface 21a and the second table 2b function as the support surface 21 (arc surface 22) described above when the compact 1 is placed on the first table 2a and the second table 2b. This configuration also makes it possible to suppress deformation of the compact during the impregnation process and to manufacture a Si-SiC composite structure having a desired shape. Furthermore, with this configuration, if only one of the first table 2a and the second table 2b is damaged, only the damaged table can be replaced, thereby reducing running costs.

[0017] As shown in FIG. 4, grooves 25 may be provided on the support surface 21 (arcuate surface 22). The grooves 25 form a gap between the compact 1 and the cradle 2 when the compact 1 is placed on the cradle 2. Therefore, gas that may be generated during the impregnation process can be smoothly discharged through the gap. As a result, the degreasing efficiency of the compact can be improved. Preferably, a plurality of grooves 25 are provided on the support surface 21. In the illustrated example, a plurality of grooves 25 are provided at intervals from each other in the circumferential direction of the support surface 21 (arcuate surface 22). In such a configuration, when the compact 1 is placed on the cradle 2, the portions of the support surface 21 where the grooves 25 are not formed come into contact with the outer surface of the compact 1.

[0018] Furthermore, any appropriate shape can be adopted for the support surface 21 depending on the shape of the molded body 1. When the molded body 1 has an elliptical cross section, the support surface 21 is an oval surface 23 having an oval shape, as shown in Fig. 5(a). Furthermore, as shown in Fig. 5(b), the receiving base 2 having the oval surface 23 can be composed of the first base 2a and the second base 2b as described above, and as shown in Fig. 5(c), the oval surface 23 can be provided with a groove 25 as described above. Furthermore, when the molded body 1 has a polygonal cross section, the support surface 21 may be composed of multiple flat surfaces, as shown in Figure 6(a). The number of flat surfaces can be set as desired depending on the shape of the molded body. Furthermore, as shown in Figure 6(b), a support table 2 having a support surface 21 composed of multiple flat surfaces can be composed of a first table 2a and a second table 2b as described above, and as shown in Figure 6(c), grooves 25 can be provided in the support surface 21 composed of multiple flat surfaces as described above.

[0019] In one embodiment, one end (an example of a first contact portion) and the other end (an example of a second contact portion) of the support surface 21 sandwich the molded body 1 in a horizontal direction perpendicular to the longitudinal direction of the molded body 1, and are in contact with the molded body 1. This makes it possible to suppress expansion of the molded body 1 in the horizontal direction during the impregnation step.

[0020] The above-mentioned deformation suppressing member is not limited to the configuration of the receiving base 2, as long as it can suppress deformation of the compact 1 during the impregnation step.

[0021] As shown in FIGS. 8 to 10 , the deformation suppressing member may be a storage container 4 capable of storing a molded body. As shown in FIG. 8 , the storage container 4 includes a first side wall 41 as an example of a first contact portion and a second side wall 42 as an example of a second contact portion. When the storage container 4 stores the molded body 1, the first side wall 41 contacts the molded body 1. When the storage container 4 stores the molded body 1, the second side wall 42 is located away from the first side wall 41 in a direction perpendicular to the longitudinal direction of the molded body 1 and contacts the molded body 1. In one embodiment, the first side wall 41 and the second side wall 42 extend vertically and contact the molded body 1 horizontally. This makes it possible to suppress expansion of the molded body in a direction perpendicular to the longitudinal direction (typically, the horizontal direction) during the impregnation process. In one embodiment, the storage container 4 further includes a bottom wall 43 as an example of a third contact portion. The bottom wall 43 is located below the molded body 1 contained in the storage container 4 and contacts the molded body 1 in the vertical direction. This makes it possible to suppress vertical expansion of the molded body during the impregnation process. The bottom wall 43 typically extends horizontally and connects the lower end of the first side wall 41 to the lower end of the second side wall 42. Therefore, the storage container 4 shown in FIG. 8 has a concave shape that opens upward and contacts one molded body 1 at three points.

[0022] As shown in FIG. 9 , the number of contact points between the storage container 4 and the molded body 1 may be three or more. In one embodiment, the storage container 4 further has two connecting walls 44, 45 in addition to the first side wall 41, the second side wall 42, and the bottom wall 43. When the storage container 4 contains the molded body 1, the two connecting walls 44, 45 come into contact with the molded body 1. Each of the connecting walls 44, 45 typically extends so as to intersect both the vertical and horizontal directions. The connecting wall 44 connects the lower end of the first side wall 41 to one end of the bottom wall 43 in the width direction. The connecting wall 45 connects the lower end of the second side wall 42 to the other end of the bottom wall 43 in the width direction.

[0023] As shown in FIG. 10 , in one embodiment, the storage container 4 can accommodate a plurality of molded bodies 1 arranged in a direction perpendicular to the longitudinal direction of the molded bodies 1 (typically, horizontally). The plurality of molded bodies 1 are in contact with one another while being accommodated in the storage container 4. In this case, the first side wall 41 contacts one of the plurality of molded bodies 1 located at one end in the direction in which the molded bodies are arranged. The second side wall 42 is located on the opposite side of the plurality of molded bodies 1 from the first side wall 41. The second side wall 42 contacts one of the plurality of molded bodies 1 located at the other end in the direction in which the molded bodies are arranged. Each of the first side wall 41 and the second side wall 42 typically contacts the corresponding molded body 1 in the horizontal direction. The bottom wall 43 is typically located below the plurality of molded bodies 1 accommodated in the storage container 4 and is in vertical contact with the plurality of molded bodies 1 collectively. This allows the storage container 4 to collectively suppress deformation of the plurality of molded bodies 1 during the impregnation process.

[0024] The above-described storage container 4 has a first side wall 41 and a second side wall 42 connected together and can accommodate the molded body 1, but the deformation suppression member may be a clamping tool 7 having the first side wall 41 and the second side wall 42 as separate bodies, as shown in Fig. 11. The clamping tool 7 can clamp the molded body 1 between the first side wall 41 and the second side wall 42 in a direction perpendicular to the longitudinal direction (typically, horizontally). This also makes it possible to suppress deformation of the molded body during the impregnation process.

[0025] When the molded body 1 has a tubular shape (specifically, a cylindrical, elliptical, or rectangular tubular shape), the deformation suppressing member may be an insertion jig 5 inserted into the internal space of the molded body 1, as shown in FIGS. 12 to 16. When the insertion jig 51 shown in FIG. 12 is inserted into the molded body 1, the entire outer surface (outer circumferential surface) of the insertion jig 51 is in contact with the inner surface (inner circumferential surface) of the molded body 1. As shown in FIG. 13, a groove 51a may be provided on the outer surface of the insertion jig 51. The groove 51a forms a gap between the insertion jig 51 and the molded body 1 when the insertion jig 51 is inserted into the molded body 1. Therefore, gas that may be generated during the impregnation process can be smoothly discharged through the gap. Preferably, a plurality of grooves 51a are provided on the outer surface of the insertion jig 51 at predetermined intervals. Furthermore, as shown in FIG. 14, the insertion jig 51 may have a hollow region at the center in a cross section perpendicular to the longitudinal direction. Furthermore, if the insertion jig 5 comes into contact with the inner surface (inner peripheral surface) of the molded body 1 at at least two locations, deformation of the molded body 1 during the impregnation process can be suppressed. As shown in FIG. 15, the insertion jig 52 comes into contact with the inner surface (inner peripheral surface) of the molded body 1 at two locations when inserted into the molded body 1. The insertion jig 52 typically has a substantially I-shape when viewed from the longitudinal direction of the molded body. Furthermore, as shown in FIG. 16, the insertion jig 53 comes into contact with the inner surface (inner peripheral surface) of the molded body 1 at three locations when inserted into the molded body 1. The insertion jig 53 typically has a substantially V-shape when viewed from the longitudinal direction of the molded body.

[0026] Furthermore, when the molded body 1 has a cylindrical shape (specifically, a cylindrical, elliptical, or rectangular cylindrical shape), the deformation suppressing member may be a support 6 that supports the molded body by hanging it, as shown in FIG. 17 . The support 6 includes a hook portion 61 as an example of a first contact portion and a support plate 62 as an example of a second contact portion. The hook portion 61 typically has a generally L-shape in side view, extends continuously upward from the support plate 62, and then bends and extends horizontally. The support plate 62 typically has a flat plate shape extending horizontally. When the support 6 supports the molded body 1, the horizontally extending portion of the hook portion 61 is inserted into the internal space of the molded body 1 and contacts the inner surface (inner peripheral surface) of the molded body 1 in the vertical direction. When the support 6 supports the molded body 1, the support plate 62 is positioned vertically spaced from the horizontally extending portion of the hook portion 61 and contacts the outer surface (outer peripheral surface) of the molded body 1 in the vertical direction. This also makes it possible to suppress deformation of the molded body during the impregnation step.

[0027] Below, the compact, the supply body, and the receiving base in the method for producing a Si-SiC composite structure will be described in detail, and then the impregnation step will be described in detail.

[0028] B. Molded object The compact is an object to be impregnated with the molten metal containing Si in the impregnation step. As described above, the compact contains SiC as a main component. In this specification, the term "SiC" is intended to include not only pure SiC but also SiC containing unavoidable impurities. The constituent material of the compact may contain Al and / or Si in addition to SiC. The SiC content in the compact is, for example, 50% by mass or more, preferably 85% by mass or more, and, for example, 100% by mass or less, preferably 95% by mass or less.

[0029] In one embodiment, as shown in FIG. 7, the formed body 1 is a honeycomb formed body 1a having a honeycomb structure. When the formed body is a honeycomb formed body, the Si-SiC composite structure can be a honeycomb structure. The honeycomb formed body 1a has a plurality of cells 14. The cells 14 extend from a first end face to a second end face of the honeycomb formed body 1a in the axial direction (length direction) of the honeycomb formed body 1a. The cells 14 have any appropriate shape in a cross section perpendicular to the axial direction of the honeycomb formed body 1a. Examples of the cross-sectional shape of the cells include triangles, rectangles, pentagons, hexagons, and other polygons. The cross-sectional shapes and sizes of the cells may all be the same, or at least some may be different.

[0030] The honeycomb formed body 1a has a cylindrical shape and has a hollow region at its center. The outer diameter of the honeycomb formed body can be appropriately set depending on the purpose. The outer diameter of the honeycomb formed body can be, for example, 20 mm to 200 mm, or for example, 30 mm to 100 mm. When the cross-sectional shape of the honeycomb formed body is not circular, the diameter of the largest inscribed circle inscribed in the cross-sectional shape (for example, polygonal) of the honeycomb formed body can be set as the outer diameter of the honeycomb structure. The length of the honeycomb formed body can be appropriately set depending on the purpose. The length of the honeycomb formed body can be, for example, 3 mm to 200 mm, or for example, 5 mm to 100 mm, or for example, 10 mm to 50 mm. The honeycomb formed body 1 a includes an outer peripheral wall 11 ; an inner peripheral wall 12 located inside the outer peripheral wall 11 ; and partition walls 13 located between the outer peripheral wall 11 and the inner peripheral wall 12 .

[0031] The outer peripheral wall 11 has a cylindrical shape. The outer surface of the honeycomb formed body 1a is the outer peripheral surface of the outer peripheral wall 11. The inner peripheral wall 12 has a cylindrical shape with a smaller diameter than the outer peripheral wall 11. The outer peripheral wall 11 and the inner peripheral wall 12 share an axis. The thickness of each of the outer peripheral wall 11 and the inner peripheral wall 12 can be appropriately set depending on the application of the honeycomb structure. The thickness of each of the outer peripheral wall 11 and the inner peripheral wall 12 can be, for example, 0.3 mm to 10 mm, or can be, for example, 0.5 mm to 5 mm. If the thickness of the outer peripheral wall and / or the inner peripheral wall is within this range, damage to the wall (e.g., cracks, breakage) due to external forces can be suppressed.

[0032] The partition walls 13 define a plurality of cells 14. More specifically, the partition walls 13 include first partition walls 13a extending radially from the inner peripheral wall 12 to the outer peripheral wall 11 and second partition walls 13b extending circumferentially, and the first partition walls 13a and the second partition walls 13b define a plurality of cells 14. The cross-sectional shape of the cells 14 is quadrangular (a rectangle elongated in the radial direction of the honeycomb formed body). With this configuration, the honeycomb formed body is prone to deformation during the impregnation process. However, because the honeycomb formed body is placed on a support during the impregnation process, deformation of the honeycomb formed body can be suppressed even if the honeycomb formed body has cells extending radially. Furthermore, although not shown, the first partition wall 13a and the second partition wall 13b may be perpendicular to each other and define cells 14 having a quadrangular (square) cross-sectional shape except for the portions in contact with the inner peripheral wall 12 and the outer peripheral wall 11.

[0033] The cell density (i.e., the number of cells 14 per unit area) in the cross section in the direction perpendicular to the axial direction of the honeycomb formed body can be appropriately set depending on the purpose. The cell density is, for example, 4 cells / cm 2 ~320 cells / cm 2 If the cell density is in this range, the strength and effective GSA (geometric surface area) of the honeycomb structure can be sufficiently ensured. The thickness of the partition walls 13 can be appropriately set depending on the application of the honeycomb structure. The thickness of the partition walls 13 is typically thinner than the thickness of each of the outer peripheral wall 11 and the inner peripheral wall 12. The thickness of the partition walls 13 can be, for example, 0.1 mm to 1.0 mm, or can be, for example, 0.2 mm to 0.6 mm. When the thickness of the partition walls is within this range, the mechanical strength of the honeycomb structure can be made sufficient, and the opening area (the total area of ​​the cells in the cross section) can be made sufficient.

[0034] The porosity of each of the outer peripheral wall 11, the inner peripheral wall 12, and the partition walls 13 can be appropriately set depending on the purpose. The porosity is, for example, 15% or more, preferably 20% or more, and for example, 50% or less, preferably 45% or less. The porosity can be measured, for example, by mercury porosimetry. If the porosity of the outer peripheral wall, the inner peripheral wall, and the partition walls is within such range, the molten metal can be impregnated into the honeycomb formed body by utilizing capillary force in the impregnation step. The densities of the outer peripheral wall 11, the inner peripheral wall 12, and the partition walls 13 (densities of the compacts) can be appropriately set depending on the purpose. 3 or more, preferably 1.8 g / cm 3 or more, for example, 2.8 g / cm 3 or less, preferably 2.6 g / cm 3 The density can be measured by, for example, mercury intrusion porosimetry. When the densities of the outer peripheral wall, the inner peripheral wall, and the partition walls are within such ranges, voids can be formed inside the outer peripheral wall, the inner peripheral wall, and the partition walls with the above-mentioned porosity.

[0035] Such a molded body (honeycomb molded body) can be produced by the following method. First, a binder and water or an organic solvent are added to an inorganic material powder containing SiC powder, and the resulting mixture is kneaded to form a clay. The clay is then molded (typically by extrusion molding) into a desired shape and dried to produce a dried body (honeycomb dried body). Next, the dried body (honeycomb dried body) is processed to a predetermined shape, thereby obtaining a molded body (honeycomb molded body) of the desired shape.

[0036] C. Supply body As described above, the supply body contains Si as a main component. The constituent material of the supply body may contain Al in addition to Si. The Si content in the supply body is, for example, 50 mass% or more, preferably 90 mass% or more, and more preferably 95 mass% or more, and is, for example, 100 mass% or less, preferably 97 mass% or less, and more preferably 96 mass% or less. When the Si content in the supply body is within this range, the molten metal containing Si can be uniformly impregnated into the entire compact in the impregnation step, and the amount of Si impregnated in the Si-SiC composite structure can be made uniform. The donor may be of any suitable shape and size that allows it to come into contact with the molded body during the impregnation step. Such a supply body can be obtained, for example, by molding (typically, press molding) inorganic material powder containing Si powder into a desired shape, and then drying it.

[0037] D. Deformation suppression member (support) The deformation suppression member is typically made of a material that is stable at the heating temperature of the impregnation step. The deformation suppression member (typically the support) preferably contains at least one material selected from carbon, boron nitride, alumina, and platinum. Furthermore, a coating layer is preferably provided on the contact surface of the deformation suppression member with the compact (typically, the support surface of the pedestal). When a coating layer is provided on the support surface, the coating layer contacts the outer surface of the compact when the compact is placed on the pedestal. The coating layer prevents the molten metal containing Si from penetrating into the deformation suppression member (typically, the pedestal) during the impregnation process. Materials for the coating layer are preferably inert (non-reactive) to the respective materials of the deformation suppression member (typically, the pedestal), the compact, and the molten metal, and more preferably, boron nitride. The thickness of the coating layer is, for example, 0.01 mm or more and 0.15 mm or less. Such a deformation suppressing member (supporting base) can be obtained by, for example, cutting, and then, if necessary, a coating layer is formed on the support surface by spraying boron nitride.

[0038] E. Impregnation process In the impregnation step, first, the formed body (honeycomb formed body) is brought into contact with the deformation suppressing member as described above, and then the supply body is brought into contact with the formed body in contact with the deformation suppressing member. The supply body can be placed at any appropriate position as long as it can come into contact with the compact during the impregnation process. For example, as shown in FIG. 1, when the compact 1 has a tubular shape (typically a cylindrical shape), the supply body 3 is placed inside the compact 1 and comes into contact with the inner peripheral surface (inner surface) of the compact 1. In this case, the hollow space of the compact can be used as a space for placing the supply body, which can further improve the packing efficiency of the compact. Also, as shown in FIG. 12, when a jig is inserted inside the compact 1, the supply body is placed outside the compact and comes into contact with the outer peripheral surface (outer surface) of the compact. The amount of the feed material used is, for example, 20 parts by mass or more, preferably 30 parts by mass or more, and for example, 80 parts by mass or less, preferably 70 parts by mass or less, relative to 100 parts by mass of the compact. If the amount of the feed material used is equal to or greater than the lower limit, the compact can be sufficiently impregnated with Si. If the amount of the feed material used is equal to or less than the upper limit, the load of the feed material can be prevented from excessively affecting the compact, and leakage of molten metal from the compact can be prevented.

[0039] Next, the compact, the supply body, and the deformation suppressing member are heated all at once. The heating temperature is, for example, 1200°C or higher, preferably 1300°C or higher, and, for example, 1600°C or lower, preferably 1500°C or lower. The heating time is, for example, 10 minutes or longer, preferably 1 hour or longer. When the heating temperature is within the above range and / or the heating time is equal to or higher than the lower limit, the molten metal containing Si can be smoothly impregnated into the compact. The upper limit of the heating time is typically 10 hours or shorter, preferably 5 hours or shorter. When the heating time is equal to or shorter than the upper limit, the production efficiency of the Si-SiC composite structure can be further improved. The impregnation step is preferably carried out under reduced pressure. When the impregnation step is carried out under reduced pressure, the molten metal containing Si can be more smoothly impregnated into the molded body. The pressure in the impregnation step is, for example, 500 Pa or less, preferably 300 Pa or less, more preferably 200 Pa or less, and typically 10 Pa or more. The impregnation step can also be carried out under normal pressure (0.1 MPa).

[0040] This allows the molded body to be impregnated with the molten metal containing Si while suppressing deformation of the molded body, resulting in the production of a Si-SiC composite structure (honeycomb structure) having a desired shape. [Industrial Applicability]

[0041] The method for manufacturing a Si-SiC composite structure according to an embodiment of the present invention can be used to manufacture various industrial products, and can be particularly suitably used to manufacture heat exchangers. [Explanation of symbols]

[0042] 1. Molded body 1a Honeycomb molded body 2 cradle 2a 1st unit 2b 2nd unit 3 Supply body 4. Containment vessel 5 Insertion jig 6 Supports 7 Clamping tool

Claims

1. the method includes a step of bringing a compact containing SiC into contact with a deformation suppressing member for suppressing deformation of the compact, and heating a supply body containing Si in a state in which the supply body is in contact with the compact, and impregnating the compact with molten metal containing Si, the deformation suppression member is a support base having a support surface that conforms to the outer shape of the molded body, The molded body is impregnated with the molten metal while the molded body is placed on the cradle. , a method for manufacturing a Si-SiC composite structure.

2. 2. The method for producing a Si-SiC composite structure according to claim 1, wherein the support surface covers 30% or more of the outer surface of the compact when the compact is placed on the pedestal.

3. The method for producing a Si-SiC composite structure according to claim 2, wherein the compact has a cylindrical shape.

4. 4. The method for producing a Si-SiC composite structure according to claim 3, wherein the compact is placed on the pedestal so that the axis of the compact is parallel to the horizontal direction.

5. The support surface has an arcuate shape, 5. The method for producing a Si-SiC composite structure according to claim 3, wherein the radius of curvature of the support surface is at least 1 / 2 of the outer diameter of the compact and is at most 1 / 2 of the outer diameter of the compact + 0.3 mm.

6. The method for producing a Si-SiC composite structure according to claim 3, wherein the supply body is placed inside the compact.

7. The method for producing a Si-SiC composite structure according to any one of claims 1 to 6, wherein a coating layer is provided on the support surface.

8. The support surface is provided with a groove, 8. The method for manufacturing a Si-SiC composite structure according to claim 1, wherein the groove forms a gap between the compact and the pedestal when the compact is placed on the pedestal.

9. the cradle includes a first base having a first surface and a second base having a second surface; The molded body is placed on the first table and the second table, 9. A method for manufacturing a Si-SiC composite structure according to claim 1, wherein the first surface and the second surface function as the support surfaces when the compact is placed on the first table and the second table.

10. The deformation suppression member is a first contact portion that contacts the molded body; 2. The method for producing a Si-SiC composite structure according to claim 1, further comprising: a second contact portion positioned away from the first contact portion in a direction perpendicular to the longitudinal direction of the compact and in contact with the compact.

11. the deformation suppressing member is capable of suppressing deformation of the plurality of molded bodies, The plurality of molded bodies are arranged in a direction perpendicular to the longitudinal direction of the molded bodies and are in contact with each other, The deformation suppression member is a first contact portion that contacts a molded body located at one end of the plurality of molded bodies; 2. A method for manufacturing a Si-SiC composite structure as described in claim 1, further comprising: a second contact portion located on the opposite side of the plurality of compacts from the first contact portion, the second contact portion contacting the compact located at the other end of the plurality of compacts.

12. 12. The method for producing a Si-SiC composite structure according to claim 10, wherein the first contact portion and the second contact portion are in contact with the compact in a horizontal direction.

13. The method for producing a Si-SiC composite structure according to claim 12, wherein the deformation suppressing member has a third contact portion that contacts the compact in a vertical direction.

14. 14. The method for producing a Si-SiC composite structure according to claim 1, wherein the deformation suppressing member contains at least one material selected from the group consisting of carbon, boron nitride, alumina, and platinum.

15. The method for producing a Si-SiC composite structure according to any one of claims 1 to 14, wherein the formed body has a honeycomb structure.

Images