Porous silicon carbide ceramic as well as preparation method and application thereof

Abstract

The invention relates to a porous silicon carbide ceramic as well as a preparation method and application thereof, the preparation method comprises the following steps: mixing silicon carbide and a sintering aid, and sequentially carrying out die filling and constant-temperature hot pressed sintering to obtain the porous silicon carbide ceramic, the pressure of the constant-temperature hot pressing sintering is 1MPa to 10MPa. The porous silicon carbide with controllable pores, uniform pore distribution and high strength can be prepared by adopting silicon carbide particles as a raw material through a particle accumulation method without adding a binder for molding and only adopting constant-temperature hot-pressed sintering and reasonably controlling the pressure of the constant-temperature hot-pressed sintering; the prepared porous silicon carbide can realize uniform adsorption of each tiny local area of a whole wafer. The preparation method provided by the invention can reduce the process equipment requirement and the production cost, and can also improve the production efficiency.

Description

Technical Field

[0001] The present invention belongs to the technical field of silicon carbide, and relates to a silicon carbide ceramic and a preparation method and application thereof, and in particular to a porous silicon carbide ceramic and a preparation method and application thereof. Background Art

[0002] The porous vacuum chuck is a bearing platform that uses the vacuum adsorption principle to fix the workpiece. The part of the vacuum chuck that transmits the vacuum is porous ceramic. The porous ceramic material is made of high-quality raw materials such as corundum sand, silicon carbide, cordierite, etc. It is a ceramic material with an open pore size and high open porosity prepared by molding and special high-temperature sintering process. It has the advantages of high temperature and high pressure resistance, acid and alkali and organic medium corrosion resistance, controllable pore structure and high open porosity. The porous ceramic is fixed in the countersunk hole of the base, and its periphery is bonded and sealed with the base. When negative pressure is applied, the workpiece can be stably adsorbed on the vacuum chuck. Therefore, the porous ceramic not only needs to have a high porosity and uniform pore distribution, but also needs to have high thermal conductivity, good flatness and parallelism, acid and alkali corrosion resistance and wear resistance. It is mainly used for thinning, etching, cutting, cleaning and other processes of wafers.

[0003] At present, the preparation methods of silicon carbide-based porous ceramics mainly include particle stacking method, pore-forming method, foaming method or freeze-drying method. Particle stacking method is one of the simplest methods for preparing silicon carbide-based porous ceramics. Its mechanism is to use the sintering characteristics of silicon carbide particles themselves, or add a small amount of binder or sintering aid to form sintering necks between silicon carbide particles, so that silicon carbide particles are stacked to form porous ceramics. The pore structure and shape mainly depend on factors such as the particle size and shape of the silicon carbide raw material, sintering temperature and molding pressure.

[0004] CN112407936A discloses a porous vacuum suction cup and a preparation method thereof. The method comprises adding a suspension stabilizer, a dispersant and a binder to a raw material with a particle size of 1 μm-25 μm, and adopting a freeze-drying method to prepare a porous vacuum suction cup. The porous vacuum suction cup can achieve stable adsorption of the adsorbed object and will not cause product defects such as concave deformation.

[0005] However, in order to obtain silicon carbide porous materials with large pores, silicon carbide particles with larger particle sizes are usually used. In the prior art, the use of silicon carbide particles with large particle sizes may make molding difficult. In addition, during the extrusion molding process, the mold wears significantly, which may cause problems such as increased production costs. Therefore, how to prepare silicon carbide porous materials with large pores at low cost is a problem that needs to be solved urgently. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a porous silicon carbide ceramic and its preparation method and application. The present invention uses silicon carbide particles as raw materials, through the particle stacking method, without adding a binder for molding, only constant temperature hot pressing sintering, and reasonable control of the constant temperature hot pressing sintering pressure, to prepare porous silicon carbide with controllable pores, uniform pore distribution and high strength. The prepared porous silicon carbide can achieve uniform adsorption of each tiny local area of ​​the whole wafer. The preparation method of the present invention can reduce process equipment requirements and production costs, and can also improve production efficiency.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a method for preparing a porous silicon carbide ceramic, the preparation method comprising the following steps:

[0009] After mixing silicon carbide and sintering aids, mold filling and constant temperature hot pressing sintering are carried out in sequence to obtain the porous silicon carbide ceramic; the constant temperature hot pressing sintering pressure is 1MPa-10MPa.

[0010] The present invention uses silicon carbide particles as raw materials, and through a particle stacking method, no binder is added for molding, and only constant temperature hot pressing sintering is used, and the pressure of constant temperature hot pressing sintering is reasonably controlled, so that porous silicon carbide with controllable pores, uniform pore distribution and high strength can be prepared, and uniform adsorption of each small local area of ​​the whole wafer can be achieved. The preparation method of the present invention can reduce process equipment requirements and production costs, and can also improve production efficiency.

[0011] Specifically, the pressure of the constant temperature hot pressing sintering can be 1 MPa, 3 MPa, 5 MPa, 7 MPa or 10 MPa, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0012] The present invention further regulates the porosity and strength of the porous silicon carbide ceramic by regulating the pressure of constant temperature hot pressing sintering. In the preferred pressure range, a porous silicon carbide ceramic with uniform pore size distribution and high strength can be obtained.

[0013] Preferably, the particle size D50 of the silicon carbide is 30 μm-200 μm, for example, 30 μm, 50 μm, 100 μm, 150 μm or 200 μm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable, preferably 100 μm-200 μm.

[0014] The present invention further regulates the porosity generated after particle accumulation and the difficulty of the sintering process by regulating the size of the silicon carbide particles, thereby further regulating the strength of the porous silicon carbide ceramic. Within the preferred silicon carbide particle size range, the sintering difficulty is low, and a porous silicon carbide ceramic with uniform pore size distribution and high strength can be obtained.

[0015] Preferably, the mass purity of the silicon carbide is 99%-99.99%, for example, 99%, 99.5%, 99.9%, 99.95% or 99.99%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0016] Preferably, the silicon carbide is pretreated before mixing.

[0017] Preferably, the heating end temperature of the pretreatment is 1900°C-2200°C, for example, it can be 1900°C, 1950°C, 2000°C, 2050°C, 2100°C or 2200°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0018] Preferably, the pretreatment insulation time is 1 h-2 h, for example, 1 h, 1.3 h, 1.5 h, 1.8 h or 2 h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0019] Preferably, after the pretreatment, spherical silicon carbide particles are obtained.

[0020] The pretreated silicon carbide particles of the present invention have good fluidity, regular particle stacking, regular pore structure and close stacking, which is conducive to further improving the uniformity of silicon carbide particles; while for untreated raw material powder, its shape is irregular and contains more edges and corners, and the fine powder in the powder forms agglomerates, and the particles are easily accumulated to form long and narrow large pores during the molding process. Therefore, the porous silicon carbide ceramics prepared by using the pretreated silicon carbide particles have further improved porosity and average pore size.

[0021] Preferably, the sintering aid comprises any one of fine silicon carbide powder, silicon powder, boron carbide, silicon dioxide, yttrium oxide or alkaline oxides, or a combination of at least two thereof. Typical but non-limiting combinations include a combination of fine silicon carbide powder and silicon powder, a combination of boron carbide and silicon dioxide, a combination of yttrium oxide and silicon dioxide, or a combination of silicon dioxide, yttrium oxide and alkaline oxides.

[0022] Preferably, the alkaline oxide comprises potassium oxide and / or sodium oxide.

[0023] Preferably, the particle size D50 of the fine silicon carbide powder is 0.5 μm-2 μm, for example, 0.5 μm, 1 μm, 1.5 μm or 2 μm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0024] Preferably, the added amount of the sintering aid is 0-15% of the mass of the silicon carbide, but does not include 0, for example, it can be 0.5%, 5%, 10%, 12% or 15%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0025] Preferably, the mixing method includes ball milling mixing and / or high-speed stirring.

[0026] Preferably, the mixing device comprises a ball mill, a mixer or a high-speed stirrer.

[0027] Preferably, the mixing method comprises wet mixing.

[0028] Preferably, the wet mixed solvent comprises water and / or ethanol.

[0029] Preferably, the mixing time is 1 h-4 h, for example, 1 h, 2 h, 3 h, 3.5 h or 4 h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0030] Preferably, the amount of the solvent added is 5%-20% of the total mass of the silicon carbide and the sintering aid, for example, it can be 5%, 10%, 12%, 15% or 20%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0031] Preferably, after mixing and before molding, drying, crushing and sieving are performed in sequence to obtain a mixed powder.

[0032] Preferably, the drying comprises oven drying.

[0033] Preferably, the drying heating end point temperature is 60°C-100°C, for example, 60°C, 70°C, 80°C, 90°C or 100°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0034] Preferably, the drying heat preservation time is 5h-12h, for example, it can be 5h, 7h, 9h, 10h or 12h, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0035] Preferably, the mesh size of the sieving is 60-100 mesh, for example, 60 mesh, 70 mesh, 80 mesh, 90 mesh or 100 mesh, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0036] Preferably, the particle size D50 of the mixed powder is 28 μm-196 μm, for example, it can be 28 μm, 50 μm, 75 μm, 100 μm, 125 μm, 150 μm, 175 μm or 196 μm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0037] Preferably, the molding die comprises a carbon die or a graphite die.

[0038] Preferably, the diameter of the mold is 100 mm-300 mm, for example, 100 mm, 150 mm, 200 mm, 250 mm or 300 mm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0039] Preferably, the heating end temperature of the constant temperature hot pressing sintering is 1450°C-2200°C, for example, it can be 1450°C, 1600°C, 1800°C, 2000°C or 2200°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0040] The present invention can control the particle size during the sintering process by regulating the endpoint temperature of constant temperature hot pressing sintering, which is conducive to forming a porous macroporous structure; further, the present invention, with the help of sintering aids, helps to reduce the endpoint temperature of constant temperature hot pressing sintering, and also helps to prepare porous silicon carbide ceramics with uniform pore size distribution and high strength during the constant temperature hot pressing sintering process.

[0041] Preferably, the holding time of the constant temperature hot pressing sintering is 1 h-2 h, for example, 1 h, 1.3 h, 1.5 h, 1.8 h or 2 h, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0042] Preferably, after the constant temperature hot pressing sintering, demoulding, machining and cleaning are performed in sequence.

[0043] As a preferred technical solution of the present invention, the preparation method comprises the following steps:

[0044] (1) Pre-spheroidizing silicon carbide at 1900° C.-2200° C. for 1 h-2 h to obtain pre-treated silicon carbide particles.

[0045] (2) Mixing a sintering aid and the pretreated silicon carbide to obtain a mixed material.

[0046] (3) The mixed material is dried, crushed and sieved in sequence to obtain a mixed powder.

[0047] (4) After the mixed powder is filled into a mold, it is placed in a hot pressing furnace and sintered at a constant temperature of 1450° C.-2200° C. and 1 MPa-10 MPa for 1 h-2 h to obtain a sintered body.

[0048] (5) Demolding, machining and cleaning the sintered body in sequence to obtain the porous silicon carbide ceramic.

[0049] Specifically, after the spheroidization pretreatment, quasi-spherical silicon carbide particles are obtained.

[0050] In a second aspect, the present invention provides a porous silicon carbide ceramic, wherein the porous silicon carbide ceramic is prepared by the preparation method described in the first aspect.

[0051] The present invention uses silicon carbide particles as the main raw material, and prepares porous silicon carbide with controllable pores, uniform pore distribution and high strength under constant temperature hot pressing conditions by a particle stacking method, which can achieve uniform adsorption of each tiny local area of ​​the entire wafer.

[0052] Preferably, the porosity of the porous silicon carbide ceramic is 20%-55%, for example, it can be 20%, 25%, 30%, 40%, 50% or 55%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0053] In a third aspect, the present invention provides an application of the porous silicon carbide ceramic as described in the second aspect, wherein the porous silicon carbide ceramic is applied to a vacuum chuck.

[0054] Compared with the prior art, the present invention has at least the following beneficial effects:

[0055] (1) The present invention uses silicon carbide particles as raw materials, and adopts a particle stacking method, without adding a binder for molding. It only adopts constant temperature hot pressing sintering, and reasonably controls the pressure of constant temperature hot pressing sintering, so as to prepare porous silicon carbide with controllable pores, uniform pore distribution and high strength, and can achieve uniform adsorption of each tiny local area of ​​the entire wafer.

[0056] (2) The preparation method of the present invention can reduce the requirements for process equipment and production costs, and can also improve production efficiency. DETAILED DESCRIPTION

[0057] For the convenience of understanding the present invention, the present invention lists the following embodiments. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0058] Example 1

[0059] This embodiment provides a method for preparing porous silicon carbide ceramics, the preparation method comprising the following steps:

[0060] (1) Spheroidizing black silicon carbide with a D50 of 100 μm and a mass purity of 99.9% at 2000° C. for 1.5 h to obtain pretreated silicon carbide particles;

[0061] (2) Weighing 10 parts by mass of fine silicon carbide powder with a particle size of 1 μm and 100 parts by mass of pretreated silicon carbide particles, adding 20 parts by mass of ethanol, and ball milling in a ball mill for 2 hours to obtain a mixture;

[0062] (3) The mixed material was dried in an oven at 80°C for 5 h, and then crushed and passed through a 100-mesh standard sieve to obtain a mixed powder with a D50 of 94 μm;

[0063] (4) After the crushed material is loaded into a graphite mold with a diameter of 150 mm, it is placed in a hot pressing furnace and sintered at a constant temperature of 1450° C. and 5 MPa for 1.5 h to obtain a sintered body;

[0064] (5) Demolding, machining and cleaning the sintered material in sequence to obtain the porous silicon carbide ceramic.

[0065] Example 2

[0066] This embodiment provides a method for preparing porous silicon carbide ceramics, the preparation method comprising the following steps:

[0067] (1) spheroidizing green silicon carbide with a D50 of 30 μm and a mass purity of 99% at 1900° C. for 2 h to obtain pretreated silicon carbide particles;

[0068] (2) Weighing 15 parts by mass of silicon dioxide and 100 parts by mass of pretreated silicon carbide particles, adding 6 parts by mass of water, and ball milling in a ball mill for 1 hour to obtain a mixture;

[0069] (3) The mixed material was dried in an oven at 60°C for 12 h, and then crushed and passed through a 100-mesh standard sieve to obtain a mixed powder with a D50 of 28 μm;

[0070] (4) After the mixed powder is loaded into a carbon mold with a diameter of 300 mm, it is placed in a hot pressing furnace and sintered at a constant temperature of 1900° C. and 10 MPa for 2 h to obtain a sintered body;

[0071] (5) Demolding, machining and cleaning the sintered material in sequence to obtain the porous silicon carbide ceramic.

[0072] Example 3

[0073] This embodiment provides a method for preparing porous silicon carbide ceramics, the preparation method comprising the following steps:

[0074] (1) Spheroidizing black silicon carbide with a D50 of 200 μm and a mass purity of 99.99% at 2200° C. for 1 h to obtain pretreated silicon carbide particles;

[0075] (2) Weighing 100 parts by mass of pretreated silicon carbide and 0.1 parts by mass of potassium oxide particles, adding 5 parts by mass of ethanol, and ball milling in a ball mill for 4 hours to obtain a mixture;

[0076] (3) The mixed material was dried in an oven at 100°C for 5 h, and then crushed and passed through a 60-degree sieve to obtain a mixed powder with a D50 of 196 μm;

[0077] (4) After the mixed powder is loaded into a graphite mold with a diameter of 100 mm, it is placed in a hot pressing furnace and sintered at a constant temperature of 2200° C. and 1 MPa for 1 h to obtain a sintered body;

[0078] (5) Demolding, machining and cleaning the sintered material in sequence to obtain the porous silicon carbide ceramic.

[0079] Example 4

[0080] The only difference between this embodiment and embodiment 1 is that, except for the particle size of black silicon carbide in step (1) being 25 μm, the rest is the same as embodiment 1.

[0081] Example 5

[0082] The only difference between this embodiment and embodiment 1 is that, except for the particle size of black silicon carbide in step (1) being 250 μm, the rest is the same as embodiment 1.

[0083] Example 6

[0084] The only difference between this embodiment and embodiment 1 is that, except that the temperature of the constant temperature hot pressing sintering in step (4) is 1400° C., the rest is the same as embodiment 1.

[0085] Example 7

[0086] The difference between this embodiment and embodiment 1 is that, except that the temperature of the constant temperature hot pressing sintering in step (4) is 2250° C., the rest is the same as embodiment 1.

[0087] Example 8

[0088] The difference between this embodiment and embodiment 1 is that, except for the constant temperature hot pressing sintering time in step (4) being 0.5 h, the rest is the same as embodiment 1.

[0089] Example 9

[0090] The difference between this embodiment and embodiment 1 is that, except for the constant temperature hot pressing sintering time in step (4) being 2.5 hours, the rest is the same as embodiment 1.

[0091] Example 10

[0092] The only difference between this embodiment and embodiment 1 is that, except that the silicon carbide particles in step (1) are not subjected to spheroidization pretreatment, the rest are the same as embodiment 1.

[0093] Comparative Example 1

[0094] The difference between this comparative example and Example 1 is that, except that the pressure of the constant temperature hot pressing sintering in step (4) is 0.5 MPa, the rest is the same as Example 1.

[0095] Comparative Example 2

[0096] The difference between this comparative example and Example 1 is that, except that the pressure of the constant temperature hot pressing sintering in step (4) is 10.5 MPa, the rest is the same as Example 1.

[0097] Comparative Example 3

[0098] The difference between this comparative example and Example 1 is that, except that the constant temperature of 1450°C in step (4) is replaced by a vertical temperature field with a starting temperature of 1450°C and a temperature gradient of 15°C, the rest is the same as Example 1.

[0099] Test Method

[0100] The porous silicon carbide ceramics prepared in Examples 1-10 and Comparative Examples 1-3 were tested for porosity, average pore size and three-point bending strength. The testing method is as follows: the porosity and average pore size of the porous silicon carbide ceramics were measured using an AutoPore IV 9500 fully automatic mercury intrusion instrument produced by Micromeritics Instruments, Inc. of the United States, and the three-point bending strength of the porous silicon carbide ceramics was measured using an AGS-X series electronic universal testing machine produced by Shimadzu of Japan. The test results are recorded in Table 1.

[0101] Table 1

[0102]

[0103]

[0104] The test results show that:

[0105] (1) It can be seen from Examples 1-10 and Comparative Examples 1-3 that the present invention uses silicon carbide particles as raw materials, and through a particle stacking method, no binder is added for molding, and only constant temperature hot pressing sintering is used, and the pressure of constant temperature hot pressing sintering is reasonably controlled, so that porous silicon carbide with controllable pores, uniform pore distribution and high strength can be prepared. The prepared porous silicon carbide can achieve uniform adsorption of each small local area of ​​the entire wafer. The preparation method of the present invention can reduce process equipment requirements and production costs, and can also improve production efficiency.

[0106] (2) It can be seen from Examples 1 and 4-5 that the porous silicon carbide ceramics prepared by further controlling the particle size of the silicon carbide raw material in the present invention not only take into account the porosity and average pore size, but also further improve the strength.

[0107] (3) It can be seen from Examples 1 and 6-9 that the average pore size of the porous silicon carbide ceramics prepared by further controlling the temperature and time of constant temperature hot pressing sintering in the present invention is further reduced and the strength is further improved.

[0108] (4) It can be seen from Examples 1 and 10 that the average pore size of the porous silicon carbide ceramics prepared by pretreating the silicon carbide particles in the present invention is further increased.

[0109] (5) It can be seen from Example 1 and Comparative Examples 1-2 that the porous silicon carbide ceramics prepared by further controlling the pressure of constant temperature hot pressing sintering in the present invention have a further improved porosity and strength.

[0110] (6) It can be seen from Example 1 and Comparative Example 3 that the present invention can reduce the process equipment requirements and production costs through constant temperature hot pressing sintering, and the prepared porous silicon carbide ceramics have both porosity and average pore size while further improving the strength.

[0111] In summary, the present invention uses silicon carbide particles as raw materials, and through the particle stacking method, no binder is added for molding, and only constant temperature hot pressing sintering is used, and the pressure of constant temperature hot pressing sintering is reasonably controlled, so that porous silicon carbide with controllable pores, uniform pore distribution and high strength can be prepared, and the prepared porous silicon carbide can achieve uniform adsorption of each small local area of ​​the whole wafer. The preparation method of the present invention can reduce process equipment requirements and production costs, and can also improve production efficiency.

[0112] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing porous silicon carbide ceramics, characterized in that: The preparation method comprises the following steps: After mixing silicon carbide and a sintering aid, mold filling and constant temperature hot pressing sintering are performed in sequence to obtain the porous silicon carbide ceramic; The constant temperature hot pressing sintering pressure is 1MPa-10MPa.

2. The preparation method according to claim 1, characterized in that: The particle size D50 of the silicon carbide is 30 μm-200 μm, preferably 100 μm-200 μm; Preferably, the mass purity of the silicon carbide is 99%-99.99%.

3. The preparation method according to claim 1 or 2, characterized in that: The silicon carbide is pre-treated before mixing; Preferably, the heating end point temperature of the pretreatment is 1900°C-2200°C; Preferably, the pretreatment holding time is 1h-2h.

4. The preparation method according to any one of claims 1 to 3, characterized in that The sintering aid includes any one or a combination of at least two of fine silicon carbide powder, silicon powder, boron carbide, silicon dioxide, yttrium oxide or basic oxide; Preferably, the particle size D50 of the fine silicon carbide powder is 0.5 μm-2 μm; Preferably, the added amount of the sintering aid is 0-15% of the mass of the silicon carbide, but excluding 0.

5. The method according to any one of claims 1 to 4, characterized in that: The mixing method includes ball milling and / or high-speed stirring; Preferably, the mixing method comprises wet mixing; Preferably, the wet mixed solvent comprises water and / or ethanol.

6. The preparation method according to any one of claims 1 to 5, characterized in that: The mold for molding comprises a carbon mold or a graphite mold.

7. The preparation method according to any one of claims 1 to 6, characterized in that: The heating end point temperature of the constant temperature hot pressing sintering is 1450°C-2200°C; Preferably, the holding time of the constant temperature hot pressing sintering is 1h-2h.

8. The preparation method according to claim 1, characterized in that: The preparation method comprises the following steps: (1) spheroidizing silicon carbide at 1900° C. to 2200° C. for 1 h to 2 h to obtain pretreated silicon carbide particles; (2) mixing a sintering aid and the pretreated silicon carbide to obtain a mixed material; (3) drying, crushing and sieving the mixed material in sequence to obtain a mixed powder; (4) After the mixed powder is filled into a mold, it is placed in a hot pressing furnace and sintered at a constant temperature of 1450° C. to 2200° C. and 1 MPa to 10 MPa for 1 h to 2 h to obtain a sintered body; (5) Demolding, machining and cleaning the sintered body in sequence to obtain the porous silicon carbide ceramic.

9. A porous silicon carbide ceramic, characterized in that: The porous silicon carbide ceramic is prepared by the preparation method according to any one of claims 1 to 8.

10. An application of the porous silicon carbide ceramic as claimed in claim 9, characterized in that: The porous silicon carbide ceramic is applied to a vacuum chuck.

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