Layered porous ceramic and layered mold therefor

Abstract

The utility model relates to the technical field of ceramic structure, concretely relates to a layered porous ceramic and layered mould thereof. The layered porous ceramic includes first porous ceramic layer, second porous ceramic layer and third porous ceramic layer which are sequentially stacked in thickness direction, the hole of first porous ceramic layer is R1 in thickness direction, the hole of second porous ceramic layer is R2, the hole of third porous ceramic layer is R3, the number of R1 is less than the number of R2, the number of R3 is less than the number of R2, at least part R1, R2, R3 are communicated, the average pore size of R1 is less than the average pore size of R2, the average pore size of R3 is less than the average pore size of R2. The layered porous ceramic presents lotus root hole like microstructure as a whole, produces negative pressure stability, and has large suction force, and is suitable for high-precision, high-reliability industrial scene.

Description

Technical Field

[0001] This utility model relates to the field of ceramic structure technology, specifically to a layered porous ceramic and its layered mold. Background Technology

[0002] Silicon wafers are a core material in the semiconductor and photovoltaic fields, and can be specifically used in components such as solar cells, integrated circuits, sensors, and displays. Silicon wafer fabrication involves processes such as dicing single-crystal silicon, chemical etching, and polishing. During fabrication, maintaining the thin silicon wafer stably on the plane of the clamping tool is fundamental for precision processing. Currently, porous ceramic chucks are commonly used as clamping tools for silicon wafers. However, existing porous ceramic chucks are mostly prepared using spray granulation or internal mixing granulation methods. The resulting porous ceramics have uncontrollable porosity and pore size, numerous internal closed openings, and uncontrolled internal channels, leading to unstable negative pressure and low suction force when used as chucks. Summary of the Invention

[0003] Therefore, the technical problem to be solved by this utility model is to overcome the defects of existing porous ceramics, such as many closed openings inside, uncontrollable porosity and pore size, unstable negative pressure and low suction when used as suction cups, so as to provide a layered porous ceramic and its layered mold.

[0004] Therefore, the present invention provides the following technical solution.

[0005] This utility model provides a layered porous ceramic, which includes a first porous ceramic layer, a second porous ceramic layer and a third porous ceramic layer stacked sequentially in the thickness direction; The pores penetrating the first porous ceramic layer in the thickness direction are counted as R1, the pores penetrating the second porous ceramic layer are counted as R2, and the pores penetrating the third porous ceramic layer are counted as R3. The number of R1s is less than the number of R2s, and the number of R3s is less than the number of R2s; At least some of R1, R2, and R3 are interconnected; The average aperture of R1 is less than the average aperture of R2, and the average aperture of R3 is less than the average aperture of R2.

[0006] Optionally, the closed pores in the first porous ceramic layer are counted as U1, the closed pores in the second porous ceramic layer are counted as U2, and the closed pores in the third porous ceramic layer are counted as U3. The number of U1 is greater than the number of U2, and the number of U3 is greater than the number of U2.

[0007] The second porous ceramic layer of this layered porous ceramic has more open pores and fewer closed pores; while the first and third porous ceramic layers have fewer open pores and more closed pores. The number of U1 and U3 layers is greater than the number of U2 layers, making it difficult for air to enter the porous ceramic during use, further providing a vacuum inside the ceramic and reducing the risk of air leakage. At the same time, the first and third porous ceramic layers have more closed pores, achieving a more closed-pore outer layer structure. This improves the surface hardness and wear resistance of the ceramic and protects the internal pore structure. Furthermore, the fewer open pores in the first and third porous ceramic layers, combined with a smaller average pore size, enhance the adhesion to the adsorption surface when used as a suction cup, forming a more effective sealing interface, preventing air leakage, and improving the uniformity and stability of the adsorption force.

[0008] Optionally, the thickness of the first porous ceramic layer is greater than or equal to the thickness of the second porous ceramic layer, and the thickness of the third porous ceramic layer is greater than or equal to the thickness of the second porous ceramic layer.

[0009] Optionally, the thickness of the first porous ceramic layer, the second porous ceramic layer, and the third porous ceramic layer is 0.2~2mm.

[0010] The aforementioned thickness configuration ensures that the overall mechanical strength of the porous ceramic is primarily borne by the thicker and stronger first and third layers, making the porous ceramic less prone to bending or breakage. Simultaneously, sufficient thickness is reserved for the second layer, the functional layer, to ensure that its adsorption performance is not weakened by excessive thinness, thus achieving an optimal balance between strength and adsorption capacity.

[0011] Optionally, the average pore size of R1 and the average pore size of R3 are 1~8μm.

[0012] Optionally, the average pore size of R2 is 5~15μm.

[0013] This utility model also provides a layered mold, which is used for the manufacture of the above-mentioned layered porous ceramic.

[0014] Optionally, the layered mold includes a mold body; The mold body is provided with a first mold layer, a second mold layer and a third mold layer stacked sequentially in the thickness direction. The first mold layer includes a solid and uniformly distributed first pipe, the second mold layer includes a solid and uniformly distributed second pipe, and the third mold layer includes a solid and uniformly distributed third pipe; the first pipe penetrates the first mold layer in the thickness direction. The second pipe penetrates the second mold layer in the thickness direction; The third pipe penetrates the third mold layer in the thickness direction; At least some of the first, second, and third pipes are interconnected; The number of first-level pipelines is less than the number of second-level pipelines, and the number of third-level pipelines is less than the number of second-level pipelines. The average diameter of the first pipe is smaller than the average diameter of the second pipe; The average diameter of the third pipe is smaller than the average diameter of the second pipe.

[0015] In each mold layer of the mold body, except for the first pipe, the second pipe, and the third pipe, the part has a porous structure with holes, so that a porous structure with holes can be formed in the corresponding part when manufacturing ceramics.

[0016] When manufacturing the layered porous ceramic using the aforementioned layered mold, the first mold layer corresponds to the first porous ceramic layer, the second mold layer corresponds to the second porous ceramic layer, and the third mold layer corresponds to the third porous ceramic layer; the first pipe corresponds to R1, the third pipe corresponds to R3, and the second pipe corresponds to R3.

[0017] Optionally, the porosity of the first mold layer is greater than that of the second mold layer, and the porosity of the third mold layer is greater than that of the second mold layer. If the porosity of the first mold layer and the third mold layer are greater than that of the second mold layer, it can help to make the first porous ceramic layer and the third porous ceramic layer of the corresponding ceramic have more closed openings, and the second porous ceramic layer has fewer closed openings.

[0018] Optionally, the mold body is made of a pyrolytic material. Using a pyrolytic material to prepare the layered mold allows for automatic and complete removal during the ceramic sintering stage, eliminating the need for complex demolding processes and avoiding the risk of damage to the precision ceramic green body during demolding. This achieves near-net-shape forming and eliminates residue contamination. Typically, but not limited to, the pyrolytic material includes at least one of polytetrafluoroethylene, polyurethane, polylactic acid, and starch. These materials exhibit excellent pyrolytic properties, completely decomposing into vapors at the sintering temperature during ceramic preparation, leaving no ash or residue. This further improves the purity and performance of the final ceramic product and reduces pore blockage or performance defects caused by mold residue. The layered mold preparation method includes 3D printing. 3D printing technology can precisely and flexibly manufacture mold cavities with complex microstructure features, further ensuring the pore structure quality of the final ceramic product and improving the consistency and repeatability of product performance.

[0019] Optionally, the average diameter of the first pipe is 1~8μm.

[0020] Optionally, the average diameter of the third pipe is 1~8μm.

[0021] Optionally, the average diameter of the second pipe is 5~15μm.

[0022] Optionally, the thickness of the first mold layer is greater than or equal to the thickness of the second mold layer, and the thickness of the third mold layer is greater than or equal to the thickness of the second mold layer.

[0023] Optionally, the thickness of the first mold layer, the second mold layer, and the third mold layer is 0.2~2mm.

[0024] The beneficial effects of this utility model are: This invention provides a layered porous ceramic comprising a first porous ceramic layer, a second porous ceramic layer, and a third porous ceramic layer stacked sequentially in the thickness direction. The number of pores penetrating the first porous ceramic layer is designated R1, the number of pores penetrating the second porous ceramic layer is designated R2, and the number of pores penetrating the third porous ceramic layer is designated R3. The number of R1 pores is less than the number of R2 pores, and the number of R3 pores is less than the number of R2 pores. At least some R1, R2, and R3 pores are interconnected. The average pore diameter of R1 is less than the average pore diameter of R2, and the average pore diameter of R3 is less than the average pore diameter of R2. The second porous ceramic layer of this layered porous ceramic has many openings, while the first and third porous ceramic layers have fewer openings, resulting in an overall lotus root-like microstructure that generates stable negative pressure and strong suction. Through the functional differentiation of the three layers—few openings on the surface for better sealing, a middle layer for flow guidance, and a bottom layer for auxiliary support—a comprehensive improvement in ceramic adsorption efficiency, stability, and lifespan can be achieved. This makes it suitable for industrial scenarios requiring high precision and high reliability, such as the handling of semiconductors and electronic devices.

[0025] Among them, R2 has a larger average pore size. The large-pore structure in the middle layer may provide a buffer, alleviate external stress, and improve the overall mechanical strength and fatigue resistance of porous ceramics. The smaller average pore sizes of R1 and R3 can better adapt to the small and uneven adsorption surface, improving applicability. At the same time, the gradient pore design with small average pore sizes of R1 and R3 and large average pore size of R2 can reduce the probability of particles entering deep pores, reduce the risk of clogging, and extend the service life of ceramics.

[0026] The layered mold provided by this utility model is used for the manufacture of the above-mentioned layered porous ceramics, which simplifies the preparation method of layered porous ceramics and facilitates mass production.

[0027] This utility model provides a layered mold, comprising a mold body; the mold body is stacked sequentially in the thickness direction with a first mold layer, a second mold layer, and a third mold layer. The first mold layer includes solid and uniformly distributed first pipes, the second mold layer includes solid and uniformly distributed second pipes, and the third mold layer includes solid and uniformly distributed third pipes. The first pipes penetrate the first mold layer in the thickness direction; the second pipes penetrate the second mold layer in the thickness direction; and the third pipes penetrate the third mold layer in the thickness direction. At least some of the first, second, and third pipes are interconnected. The number of first pipes is less than the number of second pipes, and the number of third pipes is less than the number of second pipes. The average diameter of the first pipes is less than the average diameter of the second pipes, and the average diameter of the third pipes is less than the average diameter of the second pipes. This layered mold, during ceramic preparation, helps the ceramic form a corresponding layered structure. After sintering, the solid and uniformly distributed first, second, and third pipes decompose in the obtained ceramic, forming pores penetrating the corresponding ceramic layers in the thickness direction, assisting in the formation of a structure where the second porous ceramic layer has many openings, while the first and third porous ceramic layers have fewer openings. Attached Figure Description

[0028] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the layered porous ceramic obtained in the embodiments of this utility model; Figure 2 This is a schematic diagram of the layered mold obtained in the embodiment of this utility model; Explanation of reference numerals in the attached figures: 11. First porous ceramic layer; 1101. Hole penetrating the first porous ceramic layer in the thickness direction; 22. Second porous ceramic layer; 2201. Hole penetrating the second porous ceramic layer in the thickness direction; 33. Third porous ceramic layer; 3301. Hole penetrating the third porous ceramic layer in the thickness direction; 1. First mold layer; 101. First pipe; 2. Second mold layer; 201. Second pipe; 3. Third mold layer; 301. Third pipe. Detailed Implementation

[0030] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described herein. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0031] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0032] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0033] Furthermore, the technical features involved in the different embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other.

[0034] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0035] Example 1 This embodiment provides a layered porous ceramic, as described below. Figure 1 Provide a detailed description: The layered porous ceramic provided in this embodiment includes a first porous ceramic layer 11, a second porous ceramic layer 22, and a third porous ceramic layer 33 stacked sequentially in the thickness direction. Holes 1101 penetrating the first porous ceramic layer in the thickness direction are designated R1, holes 2201 penetrating the second porous ceramic layer in the thickness direction are designated R2, and holes 3301 penetrating the third porous ceramic layer in the thickness direction are designated R3. The number of R1 is less than the number of R2, and the number of R3 is less than the number of R2. At least some R1, R2, and R3 are interconnected. The average pore size of R1 is less than the average pore size of R2, and the average pore size of R3 is less than the average pore size of R2. The second porous ceramic layer 22 of this layered porous ceramic has many openings, while the first porous ceramic layer 11 and the third porous ceramic layer 33 have fewer openings, resulting in an overall lotus root-like microstructure that generates stable negative pressure and strong suction.

[0036] In some optional embodiments, the number of closed pores in the first porous ceramic layer 11 is U1, the number of closed pores in the second porous ceramic layer 22 is U2, and the number of closed pores in the third porous ceramic layer 33 is U3; the number of U1 is greater than the number of U2, and the number of U3 is greater than the number of U2. The greater number of U1 and U3 than the number of U2 makes it difficult for air to enter the porous ceramic during use, further providing a vacuum inside the ceramic and reducing the risk of leakage; it also improves the surface hardness and wear resistance of the ceramic and protects the internal pore structure.

[0037] It should be noted that, Figure 1 The gray blocks next to each hole represent the collection of closed pores. The number of closed pores in each porous ceramic layer cannot be compared solely based on the number of gray blocks in that layer. Because each closed pore does not penetrate its respective porous ceramic layer, it is represented by a single gray block. The gray block actually contains many closed pores, but none of them penetrate their respective porous ceramic layers. The area ratio of the gray blocks in each porous ceramic layer indicates the area occupied by closed pores in that layer.

[0038] In some optional embodiments, the thickness of the first porous ceramic layer 11 is greater than or equal to the thickness of the second porous ceramic layer 22, and the thickness of the third porous ceramic layer 33 is greater than or equal to the thickness of the second porous ceramic layer 22. This thickness configuration ensures that the overall mechanical strength of the porous ceramic is mainly borne by the thicker and stronger first porous ceramic layer 11 and third porous ceramic layer 33, making the porous ceramic as a whole less prone to bending or breakage.

[0039] In some optional embodiments, the thickness of the first porous ceramic layer 11, the second porous ceramic layer 22, and the third porous ceramic layer 33 is 0.2~2mm.

[0040] In some optional embodiments, the average pore size of R1 and the average pore size of R3 are 1~8μm.

[0041] In some optional embodiments, the average pore size of R2 is 5~15μm.

[0042] Example 2 This embodiment provides a layered mold, as described below. Figure 2 Provide a detailed description: The layered mold provided in this embodiment is used for the manufacture of the layered porous ceramic described in Embodiment 1.

[0043] In some optional embodiments, a mold body is included; the mold body is provided with a first mold layer 1, a second mold layer 2, and a third mold layer 3 stacked sequentially in the thickness direction. The first mold layer 1 includes solid and uniformly distributed first pipes 101, the second mold layer 2 includes solid and uniformly distributed second pipes 201, and the third mold layer 3 includes solid and uniformly distributed third pipes 301. The first pipes 101 penetrate the first mold layer 1 in the thickness direction; the second pipes 201 penetrate the second mold layer 2 in the thickness direction; and the third pipes 301 penetrate the third mold layer 3 in the thickness direction. At least some of the first pipes 101, second pipes 201, and third pipes 301 are interconnected. The number of first pipes 101 is less than the number of second pipes 201, and the number of third pipes 301 is less than the number of second pipes 201. The average diameter of the first pipes 101 is less than the average diameter of the second pipes 201, and the average diameter of the third pipes 301 is less than the average diameter of the second pipes 201. When manufacturing the layered porous ceramic using the aforementioned layered mold, the first mold layer 1 corresponds to the first porous ceramic layer 11, the second mold layer 2 corresponds to the second porous ceramic layer 22, and the third mold layer 3 corresponds to the third porous ceramic layer 33; the first pipe 101 corresponds to R1, the third pipe 301 corresponds to R3, and the second pipe 201 corresponds to R3. In each mold layer of the mold body, the portion other than the first pipe 101, the second pipe 201, and the third pipe 301 is a porous structure with holes. Figure 2 The white area is used to create a porous structure with holes in the corresponding part during ceramic manufacturing.

[0044] In some optional embodiments, the porosity of the first mold layer 1 is greater than that of the second mold layer 2, and the porosity of the third mold layer 3 is greater than that of the second mold layer 2. The greater porosity of the first mold layer 1 and the third mold layer 3 compared to the second mold layer 2 helps to ensure that the first porous ceramic layer 11 and the third porous ceramic layer 33 have more closed openings, while the second porous ceramic layer 22 has fewer closed openings. This helps to control the porosity range of each layer of the layered porous ceramic, reduces the number of closed openings in the central part of the layered porous ceramic, and provides a stable suction force to the workpiece when the layered porous ceramic is used as a suction cup.

[0045] In some optional embodiments, the mold body is made of a pyrolytic material. Using a pyrolytic material to prepare the layered mold allows for automatic and complete removal during the ceramic sintering stage, eliminating the need for complex demolding processes and avoiding the risk of damage to the precision ceramic green body during demolding. This achieves near-net-shape forming and eliminates residue contamination. Typically, but not limited to, the pyrolytic material includes at least one of polytetrafluoroethylene, polyurethane, polylactic acid, and starch. These materials exhibit excellent pyrolytic properties, completely decomposing into vapors at the sintering temperature of ceramic preparation, leaving no ash or residue. This further improves the purity and performance of the final ceramic product and reduces pore blockage or performance defects caused by mold residue. The preparation method of the layered mold includes 3D printing. 3D printing technology can precisely and flexibly manufacture mold cavities with complex microstructure features, further ensuring the pore structure quality of the final ceramic product and improving the consistency and repeatability of product performance.

[0046] In some optional embodiments, the average diameter of the first pipe 101 is 1~8 μm.

[0047] In some optional embodiments, the average diameter of the third conduit 301 is 1~8 μm.

[0048] In some optional embodiments, the average diameter of the second pipe 201 is 5~15 μm.

[0049] In some optional embodiments, the thickness of the first mold layer 1 is greater than or equal to the thickness of the second mold layer 2, and the thickness of the third mold layer 3 is greater than or equal to the thickness of the second mold layer 2.

[0050] In some optional embodiments, the thickness of the first mold layer 1, the second mold layer 2, and the third mold layer 3 is 0.2~2mm.

[0051] Example 3 This embodiment provides a layered mold, including a mold body 3D printed from polytetrafluoroethylene (PTFE) material. The mold body comprises a first mold layer 1, a second mold layer 2, and a third mold layer 3 stacked sequentially in the thickness direction. The first mold layer 1 and the third mold layer 3 each include solid and uniformly distributed first pipes 101, the second mold layer 2 includes solid and uniformly distributed second pipes 201, and the third mold layer 3 includes solid and uniformly distributed third pipes 301. The first pipes 101 penetrate the first mold layer 1 in the thickness direction; the second pipes 201 penetrate the second mold layer 2 in the thickness direction; and the third pipes 301 penetrate the third mold layer 3 in the thickness direction. At least a portion of the first pipes 101, second pipes 201, and third pipes 301 are interconnected. The number of first pipes 101 is less than the number of second pipes 201, and the number of third pipes 301 is less than the number of second pipes 201. The porosity of the first mold layer 1 is greater than the porosity of the second mold layer 2, and the porosity of the third mold layer 3 is greater than the porosity of the second mold layer 2. The overall porosity of the mold is 60%. In each mold layer of the mold body, the portion other than the first pipe 101, the second pipe 201, and the third pipe 301 is a porous structure with holes, so that a porous structure with holes can be formed in the corresponding portion when manufacturing ceramics.

[0052] The average diameter of the first pipe 101 is 8 μm, the average diameter of the second pipe 201 is 12 μm, and the average diameter of the third pipe 301 is 8 μm.

[0053] The thickness of the first mold layer 1 is 2mm, the thickness of the second mold layer 2 is 1.8mm, and the thickness of the third mold layer 3 is 2mm.

[0054] Layered porous ceramics are prepared using the above-described layered mold, wherein the first mold layer 1 corresponds to the first porous ceramic layer 11, the second mold layer 2 corresponds to the second porous ceramic layer 22, and the third mold layer 3 corresponds to the third porous ceramic layer 33; the first pipe 101 corresponds to R1, the third pipe 301 corresponds to R3, and the second pipe 201 corresponds to R3.

[0055] The preparation method of the ceramic slurry used includes the following steps: A mixed powder is prepared, consisting of 70 wt% alumina, 10 wt% titanium dioxide, 10 wt% magnesium oxide, and 10 wt% kaolin. The mixed powder is stirred in a three-dimensional mixer for 2 hours. Then, 2% (by weight) of polyethylene glycol is added as a dispersant, and the mixture is stirred in the three-dimensional mixer for another 2 hours to obtain a primary mixture. The primary mixture is added to a ball mill jar, along with an equal mass of solvent water. Alumina ceramic grinding balls are added at a ball-to-powder mass ratio of 2:1, with a volume ratio of large grinding balls (3 mm) to medium grinding balls (1 mm) of 1:2. 2% sodium silicate binder is then added. The ball milling parameters are 150 r / min, rotating clockwise for 1 hour, counterclockwise for 1 hour, and for a total of 2 hours to obtain the ceramic slurry. The ceramic slurry is then placed in a vacuum device and evacuated to 0.1 MPa to eliminate foam, resulting in a defoamed ceramic slurry. The defoaming ceramic slurry is completely injected into a layered mold under vacuum, dried, and sintered to obtain layered porous ceramics.

[0056] The layered porous ceramic comprises a first porous ceramic layer 11, a second porous ceramic layer 22, and a third porous ceramic layer 33 sequentially stacked in the thickness direction. A pore 1101 penetrating the first porous ceramic layer in the thickness direction is designated as R1, a pore 2201 penetrating the second porous ceramic layer in the thickness direction is designated as R2, and a pore 3301 penetrating the third porous ceramic layer in the thickness direction is designated as R3. The number of R1 pores is less than the number of R2 pores, and the number of R3 pores is less than the number of R2 pores. At least some R1, R2, and R3 pores are interconnected. The average pore diameter of R1 is 8 μm, the average pore diameter of R2 is 12 μm, the average pore diameter of R3 is 8 μm, and the overall porosity is 73%. Compared with a layered mold, the overall porosity of the layered porous ceramic is increased because shrinkage and densification occur during ceramic sintering.

[0057] The number of closed pores in the first porous ceramic layer 11 is U1, the number of closed pores in the second porous ceramic layer 22 is U2, and the number of closed pores in the third porous ceramic layer 33 is U3; the number of U1 is greater than the number of U2, and the number of U1 is greater than the number of U3.

[0058] The thickness of the first porous ceramic layer 11 is 2 mm, the thickness of the second porous ceramic layer 22 is 1.8 mm, and the thickness of the third porous ceramic layer 33 is 2 mm.

[0059] The layered porous ceramic provided in this embodiment has an average pore size of 8μm for R1, 12μm for R2, and 8μm for R3. Furthermore, the number of R1 pores is less than the number of R2 pores, and the number of R3 pores is less than the number of R2 pores. This results in stable negative pressure and strong suction when used as a suction cup. The number of U1 pores is greater than the number of U2 pores, and the number of U1 pores is greater than the number of U3 pores. This makes it difficult for air to enter the porous ceramic during use, further improving the vacuum level inside the ceramic and reducing the risk of leakage. It also improves the surface hardness and wear resistance of the ceramic, protecting its internal pore structure.

[0060] Example 4 This embodiment provides a layered mold. Compared with embodiment 3, the only difference is that the average diameter of the first pipe 101 is 5μm, the average diameter of the second pipe 201 is 10μm, the average diameter of the third pipe 301 is 5μm, and the porosity of the overall mold is 65%.

[0061] Layered porous ceramics were prepared using the aforementioned layered mold. The only difference between the resulting layered porous ceramics and those of Example 3 is that the average pore size of R1 is 5 μm, the average pore size of R2 is 10 μm, and the average pore size of R3 is 5 μm, with an overall porosity of 75%. The achieved performance is consistent with that of Example 3; during use, air is less likely to enter the porous ceramic, resulting in a high vacuum level inside the ceramic, low risk of leakage, and strong suction.

[0062] Comparative Example 1 This comparative example provides a porous ceramic using a conventional mold without a special internal structure. Its length and width macroscopic dimensions are consistent with the layered mold provided in Example 3. The ceramic slurry used is based on the ceramic slurry provided in Example 3 with the addition of 40 wt% of the pore-forming agent polymethyl methacrylate mixed powder. The resulting porous ceramic has a non-layered structure and a porosity of 43%.

[0063] Because the porous ceramic provided in this comparative example does not have a layered structure, the negative pressure it generates when used as a suction cup is unstable and the suction force is relatively small.

[0064] Test Example 1 The porous ceramics from Examples 3 and 4 and Comparative Example 1 were used to test their strength, and the results are shown in Table 1. The strength test used the three-point bending strength test method, referring to ASTM C1161-13.

[0065] Table 1

[0066] It can be seen that the layered porous ceramics provided in Examples 3 and 4 have superior strength compared with the non-layered Comparative Example 1.

[0067] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A layered porous ceramic, characterized in that, The layered porous ceramic includes a first porous ceramic layer, a second porous ceramic layer, and a third porous ceramic layer that are sequentially stacked in the thickness direction; The pores penetrating the first porous ceramic layer in the thickness direction are counted as R1, the pores penetrating the second porous ceramic layer are counted as R2, and the pores penetrating the third porous ceramic layer are counted as R3. The number of R1s is less than the number of R2s, and the number of R3s is less than the number of R2s; At least some of R1, R2, and R3 are interconnected; The average aperture of R1 is less than the average aperture of R2, and the average aperture of R3 is less than the average aperture of R2.

2. The layered porous ceramic according to claim 1, characterized in that, The closed pores in the first porous ceramic layer are counted as U1, the closed pores in the second porous ceramic layer are counted as U2, and the closed pores in the third porous ceramic layer are counted as U3. The number of U1 is greater than the number of U2, and the number of U3 is greater than the number of U2.

3. The layered porous ceramic according to claim 1, characterized in that, The thickness of the first porous ceramic layer is greater than or equal to the thickness of the second porous ceramic layer, and the thickness of the third porous ceramic layer is greater than or equal to the thickness of the second porous ceramic layer.

4. The layered porous ceramic according to claim 1, characterized in that, The thickness of the first porous ceramic layer, the second porous ceramic layer, and the third porous ceramic layer is 0.2~2mm.

5. The layered porous ceramic according to claim 1, characterized in that, The average pore size of R1 and the average pore size of R3 are 1~8μm; And / or, the average pore size of R2 is 5~15μm.

6. A layered mold, characterized in that, The layered mold is used for the manufacture of the layered porous ceramic as described in any one of claims 1 to 5.

7. The layered mold according to claim 6, characterized in that, Including the mold body; The mold body is provided with a first mold layer, a second mold layer and a third mold layer stacked sequentially in the thickness direction. The first mold layer includes a solid and uniformly distributed first pipe, the second mold layer includes a solid and uniformly distributed second pipe, and the third mold layer includes a solid and uniformly distributed third pipe; the first pipe penetrates the first mold layer in the thickness direction. The second pipe penetrates the second mold layer in the thickness direction; The third pipe penetrates the third mold layer in the thickness direction; At least some of the first, second, and third pipes are interconnected; The number of first-level pipelines is less than the number of second-level pipelines, and the number of third-level pipelines is less than the number of second-level pipelines. The average diameter of the first pipe is smaller than the average diameter of the second pipe; The average diameter of the third pipe is smaller than the average diameter of the second pipe.

8. The layered mold according to claim 7, characterized in that, The porosity of the first mold layer is greater than that of the second mold layer, and the porosity of the third mold layer is greater than that of the second mold layer. And / or, the mold body is made of a pyrolytic material.

9. The layered mold according to claim 7, characterized in that, The average diameter of the first pipe is 1~8μm; And / or, the average diameter of the third pipe is 1~8μm; And / or, the average diameter of the second pipe is 5~15μm.

10. The layered mold according to claim 7, characterized in that, The thickness of the first mold layer is greater than or equal to the thickness of the second mold layer, and the thickness of the third mold layer is greater than or equal to the thickness of the second mold layer. And / or, the thickness of the first mold layer, the second mold layer, and the third mold layer is 0.2~2mm.

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