Ceramic structure

Abstract

Ceramic structure (100, 200, 300), comprising: a first lattice structure (10) made of ceramic, wherein the first lattice structure (10) comprises a plurality of through holes (14) extending in a first direction perpendicular to a thickness direction; a second lattice structure (20) made of ceramic, wherein the second lattice structure (20) comprises a plurality of through holes (24) extending in a second direction perpendicular to the thickness direction and other than the first direction; and a third lattice structure (30) made of ceramic, wherein the third lattice structure (30) comprises a plurality of through holes (34) extending in a third direction perpendicular to the thickness direction and other than the first and second directions, wherein the ceramic structure (100, 200, 300) is a one-piece formed object in which the first lattice structure (10) and the second lattice structure (20) are stacked in the thickness direction.a material of the first lattice structure (10) and the second lattice structure (20) is a Si-SiC-containing material, wherein SiC particles are a major component and the metal Si is present between the SiC particles, and the following formulas (1) and (2) are satisfied, where θ1 is an angle between the first direction and the third direction, θ2 is an angle between the second direction and the third direction, and θ3 is an angle between the first direction and the second direction: 50 degrees ≤ θ1, θ2 ≤ 70 degrees θ1 + θ2 + θ3 = 180 degrees,

Description

Technical field

[0001] This application claims priority over Japanese patent application No. 2020-000554, filed on January 6, 2020, the contents of which are incorporated into the present application by reference. The present invention discloses techniques relating to ceramic structures, in particular ceramic structures with lattice structures. State of the art

[0002] International publication no. WO2018 / 047784 (hereinafter referred to as patent document 1) discloses a ceramic structure with a lattice structure (honeycomb structure). The ceramic structure with a lattice structure is lightweight and high-strength. Summary of the invention: Technical problem

[0003] Fig. Figure 8 schematically shows the ceramic structure from patent document 1. As in Fig. Figure 8 shows a ceramic structure 400 comprising partitions 422 extending in one direction (Y-direction) between a front layer 402 and a rear layer 404. The lattice structure is composed of the front layer 402, the rear layer 404, and the partitions 422. Furthermore, a plurality of through-holes 424 extending in the Y-direction are defined by the front layer 402, the rear layer 404, and the partitions 422. The ceramic structure from patent document 1 is a one-piece formed object and is manufactured by extrusion. The ceramic structure 400 is lightweight due to the through-holes 424. The lattice structure also makes the ceramic structure 400 highly strong.In particular, the ceramic structure 400 is high-strength in the extension direction of the partitions 422 (the through holes 424) (in the direction of the Y-axis) and in a thickness direction perpendicular to the front layer 402 (the rear layer 404) (in the direction of the Z-axis). However, in the direction of the X-axis (direction perpendicular to the Y-axis and the Z-axis directions), the ceramic structure 400 is relatively weak, especially with respect to shear forces in the X-axis direction. Because the ceramic structure 400 is relatively weak in this specific direction, its versatility is limited (with few possible applications). The present application aims to provide techniques for producing ceramic structures with greater versatility. Solution to the technical problem

[0004] A ceramic structure disclosed in the present application may comprise a first ceramic lattice structure comprising a plurality of through-holes extending in a first direction perpendicular to a thickness direction; and a second ceramic lattice structure comprising a plurality of through-holes extending in a second direction perpendicular to the thickness direction and other than the first direction. The first lattice structure and the second lattice structure may be stacked in the thickness direction.

[0005] A ceramic structure disclosed in the present application can be a one-piece ceramic structure in which a plurality of ceramic lattice structures, each comprising a plurality of through-holes extending in a direction perpendicular to a thickness direction, are stacked in the thickness direction. In this ceramic structure, the lattice structures can be stacked such that their through-holes extend in two or more directions perpendicular to the thickness direction. List of characters Fig. Figure 1 is a perspective view of a ceramic structure according to a first embodiment; Fig. 2 is a partially enlarged view of a grid structure; Fig. Figure 3 shows a concentration distribution of a certain element contained within a frame of a lattice structure; Fig. Figure 4 is an explanatory diagram of the positional relationship between first through holes and second through holes; Fig. Figure 5 is a perspective view of a ceramic structure according to a second embodiment; Fig. Figure 6 is an explanatory diagram of the positional relationship between the first and third through holes; Fig. Figure 7A is a perspective view of a ceramic structure according to a third embodiment; Fig. 7B is a perspective view of the ceramic structure according to the third embodiment, viewed from a different angle than the angle from Fig. 7A; and Fig. Figure 8 is an explanatory diagram of the features of a conventional lattice structure. Description of embodiments

[0006] A ceramic structure disclosed in the present application can comprise a plurality of ceramic lattice structures, each comprising a plurality of through-holes extending in a direction perpendicular to a thickness direction, and the lattice structures can be stacked in the thickness direction. The ceramic structure can be a one-piece formed object into which the lattice structures are integrated. The one-piece formed object is a post-firing object with integrated lattice structures, produced by firing a pre-firing object into which the lattice structures are integrated. Furthermore, the lattice structures can be stacked such that their through-holes extend in two or more directions perpendicular to the thickness direction.This means that this ceramic structure can comprise at least a first ceramic lattice structure comprising a plurality of through-holes extending in a first direction perpendicular to the thickness direction; and a second ceramic lattice structure comprising a plurality of through-holes extending in a second direction perpendicular to the thickness direction and different from the first direction. The ceramic structure can also comprise a third ceramic lattice structure comprising through-holes extending in a third direction (third direction ≠ first and second direction), a fourth ceramic lattice structure comprising through-holes extending in a fourth direction (fourth direction ≠ first, second, and third direction), and / or the like.

[0007] Each lattice structure can comprise a front layer, a back layer, and partitions that connect the front and back layers and extend in a direction perpendicular to the thickness direction. The multitude of through-holes can be defined by the front layer, the back layer, and the partitions. The front layer of a given lattice structure can also serve as the back layer of a lattice structure stacked on top of that lattice structure in the thickness direction. That is, if the second lattice structure is stacked on top of the front layer of the first lattice structure, the front layer of the first lattice structure can also be the back layer of the second lattice structure. The front and back surfaces of the ceramic structure can be flat.

[0008] In the ceramic structure described above, the partitions defining the wall surfaces of the through-holes extend in two or more directions perpendicular to the thickness direction. Therefore, if a force is applied to a particular lattice structure in a direction where that lattice structure is relatively weak, another lattice structure can compensate for the lack of strength. Focusing on a particular lattice structure, this structure is especially weak against a force applied to it in a specific direction perpendicular to both the thickness direction and the direction of extension of its through-holes (the partitions) (this specific direction is referred to below as the lateral direction).In the ceramic structure described above, however, a second lattice structure stacked on top of the first resists the force applied in a lateral direction, thus improving the strength balance in one surface direction of the ceramic structure. Therefore, the ceramic structure described above can solve the problem that conventional ceramic structures are "weak to a force applied in a specific direction" and can be used in various applications. In other words, the ceramic structure described above is highly versatile.

[0009] Lattice structures with through holes extending in the same direction can be stacked successively in the thickness direction. For example, initial lattice structures, each comprising through holes extending in a first direction, can be stacked successively in the thickness direction. That is, the lattice structures can be stacked in any order, as long as they are stacked such that their through holes extend in at least two directions perpendicular to the thickness direction. However, to compensate for the lack of strength in the lateral direction in a particular lattice structure, it is preferred that other lattice structures, whose through holes extend in a different direction than the direction of the through holes of the particular lattice structure, be stacked on both sides of the particular lattice structure.This means that preferably second grid structures, whose through-holes extend in a second direction that differs from the first direction, are stacked on both sides of the first grid structure with the through-holes extending in the first direction.

[0010] As described, the ceramic structure comprises the through-holes, which extend in at least two directions (first direction and second direction). The fact that the first and second directions are not parallel to each other improves the strength balance of the ceramic structure in the surface direction. For example, if an angle (acute angle) between the first and second directions is 10 degrees or more and 90 degrees or less, the first and second lattice structures compensate for the difference in strength between them, and the strength balance in the surface direction can thus be advantageously improved.In particular, if the angle (acute angle) between the first direction and the second direction is 80 degrees or more and 90 degrees or less, that is, if the first direction and the second direction are almost perpendicular to each other, the strength balance in the surface direction can be improved even more favorably.

[0011] If a ceramic structure includes through-holes extending in three or more distinct directions, any two of these directions can satisfy the above relationship. For example, a ceramic structure comprising a first lattice structure with first through-holes extending in a first direction; a second lattice structure with through-holes extending in a second direction (≠ first direction); and a third lattice structure with through-holes extending in a third direction (≠ first and second direction) can satisfy the following formulas (1) and (2), where θ1 is an angle between the first direction and the third direction, θ2 is an angle between the second direction and the third direction, and θ3 is an angle between the first direction and the second direction.Fulfilling the following formulas (1) and (2) means that at least the angle θ3 between the first through holes and the second through holes (between the first direction and the second direction) is 60 degrees or more, which compensates for the lack of strength between them in the lateral direction. 50 degrees ≤ θ1, θ2 ≤ 70 degrees θ1+θ2+θ3=180 degrees

[0012] The lattice structures of the ceramic structure can be made of the same material. For example, the lattice material can be a SiC-containing material, a multi-containing material, a ZrO2-containing material, or a Si-SiC-containing material. Here, "Si-SiC-containing material" refers to a material that contains SiC particles as its main component and in which the metal Si is present between the SiC particles. The lattice structures made of the Si-SiC-containing material reduce open porosity in a surface layer section of a frame of each lattice structure, thus improving the strength of the lattice structures. The open porosity in the frame of each lattice structure can be, for example, less than 5%, 3% or less, or preferably 1% or less. The frames of the lattice structures may be essentially non-porous.A porosity of less than 5% in the frames further improves their strength and thermal conductivity. The open porosity within each lattice structure can be measured according to JISR 1655 (Test method for the pore size distribution of fine ceramic green bodies by mercury porosimetry).

[0013] As described, the through-holes of the lattice structures extend in two or more directions perpendicular to the thickness direction, even though the ceramic structure disclosed in the present application is a one-piece formed article with integrated lattice structures. Such a ceramic structure can be produced, for example, by forming a combustible material into a desired shape, impregnating this material with a ceramic material (ceramic slip) to produce an intermediate, and then firing this intermediate. Examples of combustible material include paper, fabric, and resin. Depending on the combustible material used, a component(s) of a porous material tends to remain within the frames, in contrast to the surface layer sections of the lattice structure frames.Thus, at least one element, carbon and calcium (elements typically found in a combustible porous material), can be present in greater quantities in the frames than in the surface layer sections of the frames of the lattice structures. For example, if the ceramic structure (lattice structures) consists of the Si-SiC-containing material, the majority of the surface layer sections of the frames consist of SiC (more than 50 wt.%) and the remainder of the metal Si, whereas the majority of the frames consist of the metal Si and the remainder of carbon and / or calcium.

[0014] As described, in the ceramic structure disclosed in the present application, the lattice structures, each comprising a plurality of through-holes, are stacked in the thickness direction. This allows the ceramic structure to be lightweight and improves thermal insulation in the thickness direction (reducing the thermal conductivity between the front and back surfaces). Furthermore, since the lattice structures are stacked such that their through-holes extend in a plurality of directions, the strength balance in the surface direction can be improved. By exploiting these properties, the ceramic structure can be used effectively as a thermal insulation element (or as a component of a thermal insulation element).By exploiting the property that the ceramic structure is a single-piece formed object, but that the through-holes extend in a multitude of directions, the ceramic structure can also be excellently used as a heat exchange element in a heat exchanger. When the ceramic structure is used as a heat exchange element, the through-holes of the first grid structure serve as flow paths for a first heat transfer medium, and the through-holes of the second grid structure serve as flow paths for a second heat transfer medium, thus allowing heat exchange between the first and second heat transfer media. When the ceramic structure is used as a heat exchange element, the material of the ceramic structure is preferably a SiC-containing material or a Si-SiC-containing material with high thermal conductivity. embodimentsFirst embodiment

[0015] With reference to Fig. 1 to Fig. Section 4 describes a ceramic structure 100. Even if the in Fig. If the ceramic structure 100 shown is essentially cubic, the ceramic structure 100 can have a flat plate shape in which the size of a front surface 2 and a back surface 4 (the length in the direction of the X-axis and the length in the direction of the Y-axis) is significantly larger than a thickness (the length in the direction of the Z-axis).

[0016] As in Fig. As shown in Figure 1, the ceramic structure comprises 100 first lattice structures 10 and second lattice structures 20. The first lattice structures 10 and the second lattice structures 20 are stacked alternately in one thickness direction (direction of the Z-axis). That is, apart from the lattice structures positioned at the ends in the thickness direction, the second lattice structures 20 are stacked on both sides of each first lattice structure 10, and the first lattice structures 10 are stacked on both sides of each second lattice structure 20. The first lattice structures 10 and the second lattice structures 20 have essentially the same structure, except for the extension directions of their through-holes. The first lattice structures 10 each comprise a plurality of first through-holes 14 extending in the direction of the Y-axis (an example of the first direction).The first through-holes 14 are defined by a front layer, a back layer, and partitions 12 located between the front and back layers of each first lattice structure 10. The second lattice structures 20 each comprise a plurality of second through-holes 24 extending in the direction of the X-axis (an example of the second direction) perpendicular to the direction of the Y-axis and the direction of the Z-axis. The second through-holes 24 are defined by a front layer, a back layer, and partitions 22 located between the front and back layers of each second lattice structure 20.

[0017] As in Fig. As shown in Figure 2, in each lattice structure 10, 20, the plurality of through-holes 14 (24) are formed by the partitions 12, 22, which are connected to a front layer 16 and a rear layer 18. As described, the first lattice structures 10 and the second lattice structures 20 have essentially the same structure; therefore, a first lattice structure 10 is described below. The partitions 12 are tilted and connected to the front layer 16 and the rear layer 18, forming a lattice structure (the first lattice structure 10). The front layer 16, the rear layer 18, and the partitions 12 are formed in one piece, and there are no discernible boundaries between the front layer 16 and the partitions 12, nor between the rear layer 18 and the partitions 12.There are also no discernible boundaries between the front layer 16 of the first lattice structure 10 and the back layer 18 of the second lattice structure 20, nor between the back layer 18 of the first lattice structure 10 and the front layer 16 of the second lattice structure 20. That is to say, the in . Fig. The ceramic structure 100 shown is a one-piece formed object into which the first lattice structures 10 and the second lattice structures 20 are integrated. If the in Fig. If the lattice structure 10, 20 shown in Figure 2 is positioned at the foremost layer (at the end of the +Z-axis direction) of the ceramic structure 100, then the front layer 16 is the front surface 2 of the ceramic structure 100. Similarly, if the Fig. 2 shown lattice structure 10, 20 is positioned at the rearmost layer (at the end of the direction of the -Z-axis) of the ceramic structure 100, the rear layer 18 being the rear surface 4 of the ceramic structure 100.

[0018] The ceramic structure 100 is produced by impregnating a combustible base material, such as paper, with SiC slurry to form an intermediate product, and subsequently firing this intermediate product in contact with the metal Si. A large portion of the surface area of ​​a frame (the front layers 16, the rear layers 18, the partitions 12) of the ceramic structure 100 thus consists of SiC, and the remainder of Si. The majority within the frame consists of the metal Si, and the remainder of an element (carbon and / or calcium) contained in the base material. A surface of the frame has an open porosity of 1% or less.

[0019] Fig. Figure 3 shows a concentration distribution of a component of the base material contained within the framework of the ceramic structure 100. The abscissa of the diagram represents the thickness of the framework (e.g., a thickness of 31 of the front layer 16, a thickness of 32 of the in Fig. The 2 partition walls shown (12) represent the distance (%) from one end to the other. The ordinate represents the proportion of an element (C, Ca) that originates from the base material. As in Fig. As shown in Figure 3, “C” and “Ca” are barely present in the surface section of the frame. “C” and “Ca” begin to appear at a certain depth from the surface of the frame and increase towards the center of the frame. (Modification of ceramic structure 100)

[0020] As in Fig. As shown in Figure 1, in the ceramic structure 100, the first through holes 14 extend in the direction of the Y-axis and the second through holes 24 extend in the direction of the X-axis. That is, in the ceramic structure 100, the angle between the direction of extension of the first through holes 14 (first direction) and the direction of extension of the second through holes (second direction) is 90 degrees. However, the angle between the first direction and the second direction may not be 90 degrees. As shown in Fig. As shown in Figure 4, the first lattice structures 10 and the second lattice structures 20 can compensate for a loss of strength between them, as long as the angle of the second direction (extension direction of the second through-holes 24) with respect to the first direction (extension direction of the first through-holes 14) lies within a range α1 of 10 degrees or more to 90 degrees or less. If the angle of the second direction with respect to the first direction lies within a range α2 of 80 degrees or more and 90 degrees or less (i.e., is essentially a right angle), the strength compensation effect of the first lattice structures 10 and the second lattice structures 20 is maximized.

[0021] In the ceramic structure 100, lattice structures with through holes extending in the same direction can be stacked successively in the thickness direction. That is, two or more first lattice structures 10 (or second lattice structures 20) can be stacked successively in the thickness direction. In this case, the successively stacked first lattice structures 10 (or second lattice structures 20) can differ in thickness and / or the size of the through holes. Second embodiment

[0022] With reference to Fig. Section 5 describes a ceramic structure 200. Ceramic structure 200 is a modification of ceramic structure 100 and has a third lattice structure 30 situated between a first lattice structure 10 and a second lattice structure 20. For ceramic structure 200, the same elements as for ceramic structure 100 have the same reference numerals as those used for the elements of ceramic structure 100, and the description of these elements can be omitted.

[0023] The third lattice structure 30 comprises a plurality of third through-holes 34 extending in a third direction. The direction of extension of the third through-holes 34 (third direction) differs from the direction of extension of the first through-holes 14 (first direction: the Y-axis direction) and the direction of extension of the second through-holes 24 (second direction: the X-axis direction). In the ceramic structure 200, the angle between the third through-holes 34 and the first through-holes 14 is 45 degrees, and the angle between the third through-holes 34 and the second through-holes 24 is also 45 degrees. (Modification of the second embodiment)

[0024] In ceramic structure 200, the stacking sequence of the lattice structures 10, 20, 30 can be different. As in ceramic structure 100, in ceramic structure 200, lattice structures with through holes extending in the same direction can be stacked successively in the thickness direction. For example, the first lattice structures 10 can be stacked successively in the thickness direction. In this case, the successively stacked lattice structures 10 can differ in thickness and / or the size of the through holes.

[0025] In the ceramic structure 200, the direction of extension of the first through holes 14 (first direction), the direction of extension of the second through holes 24 (second direction), and the direction of extension of the third through holes 34 (third direction) can also differ. These directions are set such that the sum of the angles (θ1 + θ2 + θ3) equals 180 degrees, where θ1 is an angle between the first direction and the third direction, θ2 is an angle between the second direction and the third direction, and θ3 is an angle between the first direction and the second direction. Furthermore, as in Fig. As shown in Figure 6, the angle θ1 is set to 50 degrees or less and the angle θ2 to 70 degrees or less. The angle θ3 is set to 60 degrees or more. That is, the extension directions of the through holes 14, 24, and 34 are adjusted so that the following formulas (1) and (2) are satisfied. Satisfying formulas (1) and (2) means that at least the angle θ3 is set to 60 degrees or more, and the lattice structures 10, 20, and 30 can thus compensate for the lack of strength between them. 50 degrees ≤ θ1, θ2 ≤ 70 degrees θ1+θ2+θ3=180 degrees Third embodiment

[0026] With reference to Fig. 7A and Fig. 7B describes a ceramic structure 300. Fig. 7B shows a perspective view (with a surface area of ​​50) taken from the opposite side of the image in Fig.The ceramic structure 300 is considered as shown on page 7A. It is a modification of ceramic structures 100 and 200 and, like ceramic structure 200, has a third lattice structure 330 situated between a first lattice structure 310 and a second lattice structure 320. For ceramic structure 300, the same elements as those of ceramic structures 100 and 200 have the same reference symbols with the same last two digits as those of the reference symbols for the elements of ceramic structures 100 and 200, and the description of these elements can be omitted.

[0027] In ceramic structure 300, the shape of a front surface 302 and a back surface 304 is an equilateral triangle. Ceramic structure 300 comprises lattice structures 310, 320, and 330, whose through-holes extend in different directions. The angle between the direction of extension of the through-holes 14 of the first lattice structure 310 (first direction) and the direction of extension of the through-holes 24 of the second lattice structure 320 (second direction) is 60 degrees. The angle between the direction of extension of the through-holes 14 of the first lattice structure 310 (first direction) and the direction of extension of the through-holes 34 of the third lattice structure 330 (third direction) is also 60 degrees. Thus, the angle between the second and third directions is also 60 degrees. Ceramic structure 300 satisfies the above formula (2).In the ceramic structure 300, the through-holes can be arranged perpendicular to the side surfaces of the ceramic structure 300. If the ceramic structure 300 is used, for example, as a heat exchanger element in which a fluid (heating medium) flows through the through-holes, the contact resistance of the fluid can thus be reduced.

[0028] While specific examples of the present disclosure have been described in detail above, these examples are merely illustrative and do not limit the scope of the claims. The technology described in the claims also includes various changes and modifications to the specific examples described above. The technical elements explained in the present description or drawings offer technical benefits either independently or through various combinations. The present disclosure is not limited to the combinations described at the time the claims were filed. Furthermore, the examples shown in the present description or drawings are intended to fulfill several objectives simultaneously, and the fulfillment of any one of these objectives confers technical benefits on the present disclosure. Reference symbol list 10 First lattice structure 14 through holes of the first grid structure 20 Second lattice structure 24 through holes of the second grid structure 100 ceramic structure QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2020000554

[0001] WO 2018 / 047784

[0002]

Claims

[1] Ceramic structure comprising: a first lattice structure made of ceramic, the first lattice structure comprising a plurality of through holes extending in a first direction perpendicular to a thickness direction, and a second lattice structure made of ceramic, the second lattice structure comprising a plurality of through-holes extending in a second direction perpendicular to the thickness direction and different from the first direction, wherein the ceramic structure is an integrally molded article in which the first lattice structure and the second lattice structure are stacked in the thickness direction. [2] The ceramic structure according to claim 1, wherein the second lattice structures are stacked on both sides of the first lattice structure in the thickness direction. [3] The ceramic structure according to claim 1 or 2, wherein an angle between the first direction and the second direction is 10 degrees or more and 90 degrees or less. [4] The ceramic structure according to claim 3, wherein the angle between the first direction and the second direction is 80 degrees or more and 90 degrees or less. [5] The ceramic structure according to any one of claims 1 to 4, wherein a material of the first lattice structure and the second lattice structure is a Si-SiC-containing material, wherein SiC particles are a main component and the metal Si is present between the SiC particles. [6] Ceramic structure according to one of claims 1 to 5, wherein a surface layer portion of a frame of the first lattice structure has an open porosity of 5% or less, and a surface layer portion of a frame of the second lattice structure has an open porosity of 5% or less. [7] A ceramic structure according to any one of claims 1 to 6, further comprising: a third lattice structure made of ceramic, the third lattice structure comprising a plurality of through-holes extending in a third direction perpendicular to the thickness direction and different from the first and second directions, and wherein the following formulas (1) and (2) are satisfied, where θ1 is an angle between the first direction and the third direction, θ2 is an angle between the second direction and the third direction, and θ3 is an angle between the first direction and the second direction: 50 degrees≤θ1 or θ2≤70 degrees θ1+θ2+θ3=180 degrees [8] Ceramic structure comprising: a plurality of ceramic grid structures, the grid structures each comprising a plurality of through-holes extending in a direction perpendicular to a thickness direction, wherein the ceramic structure is a one-piece molded article, the lattice structures are stacked in the thickness direction, and the lattice structures are stacked such that the through-holes extend in two or more directions perpendicular to the thickness direction. [9] Heat exchange element comprising: the ceramic structure according to any one of claims 1 to 8, wherein the through holes of the first grid structure are flow paths for a first heat medium, and the through holes of the second grid structure are flow paths for a second heat medium. [10] A thermal insulation element comprising the ceramic structure according to any one of claims 1 to 8.