Alumina vacuum ceramic sucker and preparation method thereof

Abstract

The invention discloses an alumina vacuum ceramic sucker and a preparation method thereof, the preparation method comprises the following steps: mixing ceramic powder, carbon fiber, paraffin, polyethylene, polypropylene and stearic acid to obtain a feed; then, the feed is subjected to FDM 3D printing, a printed green body is cut into sheets, and a porous ceramic green body is obtained through solvent degreasing; and covering the surface of a porous ceramic body with the granulation powder, and carrying out dry pressing molding, isostatic pressing molding and sintering to obtain the alumina vacuum ceramic sucker. The alumina vacuum ceramic sucker has the advantages of high bonding strength, large air flux, excellent high-temperature dimensional stability and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of ceramic materials, and in particular relates to an alumina vacuum ceramic suction cup and a preparation method thereof. Background Art

[0002] Advanced ceramic materials have many excellent properties such as high temperature resistance, high hardness, corrosion resistance, good chemical stability and wear resistance. Ceramic suction cups, as one of the sheet clamping methods for silicon wafers, glass wafers, etc. used in the electronics industry, have obvious advantages over other metal suction cups and plastic suction cups. They are widely used in semiconductor photolithography etching, wafer thinning, wafer inspection, and laser processing.

[0003] With the rapid development of semiconductor technology, higher and higher requirements are put forward for vacuum ceramic suction cups, mainly including high light weight, high shape and position accuracy, high dimensional stability and other aspects. At the same time, the vacuum suction cup clamps the product through "negative pressure", and the air flux has a significant impact on it. At present, the preparation method of vacuum ceramic suction cups is mainly to use a CNC machining center to process the porous ceramics and the ceramic matrix separately, and then use resin or sealing glass to bond the porous ceramics and the ceramic matrix together, which will result in a weak bond between the porous ceramics and the matrix, which is easy to fall off during high-temperature use, or, due to the different thermal expansion coefficients of the binder and the ceramic, the high-temperature dimensional stability of the vacuum suction cup is poor. Therefore, finding a vacuum ceramic suction cup with high bonding strength, large air flux and excellent high-temperature dimensional stability is the key to achieving widespread application of vacuum ceramic suction cups. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide an alumina vacuum ceramic suction cup with high bonding strength, large air flux and excellent high-temperature dimensional stability and a preparation method thereof.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions.

[0006] A method for preparing an alumina vacuum ceramic chuck comprises the following steps:

[0007] S1, mixing ceramic powder, carbon fiber, paraffin, polyethylene, polypropylene and stearic acid, crushing and sieving to obtain feed;

[0008] S2, performing FDM 3D printing on the feed obtained in step S1, and baking the feed to obtain a printed body; wherein the printing direction of each layer of the FDM 3D printing is consistent, and each layer is stacked layer by layer;

[0009] S3, cutting the printed blank obtained in step S2 into sheets to obtain a sheet blank; the cutting direction is a direction perpendicular to the printing path;

[0010] S4, performing solvent degreasing on the sheet-like body obtained in step S3 to obtain a porous ceramic body;

[0011] S5, covering the surface of the porous ceramic body obtained in step S4 with granulated powder, and performing dry pressing to obtain a dry pressed body; the granulated powder is alumina powder;

[0012] S6, isostatically pressing the dry pressed green body obtained in step S5 to obtain an isostatically pressed green body;

[0013] S7, sintering the isostatically pressed green body obtained in step S6 to obtain an alumina vacuum ceramic suction cup.

[0014] In the above-mentioned preparation method, preferably, in step S1, the amount of each raw material added is calculated by mass percentage, ceramic powder 50% to 80%, carbon fiber 10% to 30%, paraffin 5% to 15%, polyethylene 1% to 5%, polypropylene 0 to 5%, and stearic acid 0.5% to 2%.

[0015] In the above-mentioned preparation method, preferably, in step S1, the ceramic powder includes alumina powder and a sintering aid, the mass percentage of the sintering aid in the ceramic powder is 1% to 10%, the sintering aid is at least one of silicon dioxide, calcium oxide, magnesium oxide and titanium oxide, the diameter of the carbon fiber is 5μm to 8μm, the length of the carbon fiber is 1mm to 5mm, and the particle size of the alumina powder is 500 mesh to 2000 mesh.

[0016] In the above preparation method, preferably, in step S5, the pressure of the dry pressing is 30 MPa to 50 MPa, and the purity of the alumina powder is greater than 99.5%.

[0017] In the above preparation method, preferably, in step S6, the pressure of the isostatic pressing is 150 MPa to 200 MPa, and the holding time of the isostatic pressing is 10 min to 30 min.

[0018] In the above preparation method, preferably, in step S7, the sintering temperature is 1550°C to 1650°C, the sintering time is 2h to 5h, the heating rate during the sintering process is 0.1°C / min to 4°C / min, and the sintering is carried out under air conditions.

[0019] In the above preparation method, preferably, in step S1, the mixing temperature is 140°C to 200°C, the mixing time is 2h to 4h, and the particle size of the feed is less than 5mm.

[0020] In the above-mentioned preparation method, preferably, in step S2, the molding mode of the FDM3D printing is fused deposition molding, and the process parameters of the fused deposition molding are: extrusion temperature 160℃~200℃, hot bed temperature 60℃~100℃, printing speed 10mm / s~30mm / s; hot air is introduced during the fused deposition molding process, and the process parameters of the hot air are: hot air temperature 100℃~150℃, hot air pressure 0.1Bar~0.5Bar; the baking temperature is 60℃~120℃, and the baking time is 0.5h~2h.

[0021] In the above preparation method, preferably, in step S3, the thickness of the sheet-like green body is 2 mm to 20 mm;

[0022] In step S4, the specific process of the solvent degreasing is: immersing the sheet-like green body obtained in step S3 in kerosene; the immersion temperature is 30° C. to 60° C., and the immersion time is 16 h to 48 h.

[0023] As a general technical concept, the present invention also provides an alumina vacuum ceramic suction cup prepared by the above preparation method. The alumina vacuum ceramic suction cup of the present invention has a porous structure, and the pore structure is mainly long columnar pores, which can be ventilated and has excellent adsorption force after vacuum.

[0024] Compared with the prior art, the advantages of the present invention are:

[0025] (1) The present invention provides a method for preparing an alumina vacuum ceramic suction cup, wherein ceramic powder and carbon fiber are used as raw materials for mixing, and the feed containing the fiber is 3D printed in the same direction to align the fibers. The carbon fiber is used as a pore-forming agent, and the fibers can be removed in the subsequent sintering process, leaving oriented long columnar pores, thereby improving the gas flux of the porous ceramic material; the printed blank is cut into sheets, and the sheet blank is not prone to defects in the subsequent degreasing and sintering process. After solvent degreasing, a porous ceramic blank is obtained; then, the alumina powder granulation powder is covered on the surface of the porous ceramic blank, dry pressing, isostatic pressing, and sintering are performed. During the dry pressing process, the pressure difference is used to combine the alumina powder-molded matrix with the porous ceramic blank, and the isostatic pressing is further used to promote the combination. After sintering, a high-strength connection between the porous ceramic blank and the alumina powder matrix blank is achieved. The alumina vacuum ceramic suction cup prepared by the present invention has the advantages of high bonding strength, large gas flux, and excellent high-temperature dimensional stability.

[0026] (2) The preparation method of the present invention optimizes the dosage of ceramic powder, carbon fiber, paraffin wax, polyethylene, polypropylene, and stearic acid, that is, the addition amount of each raw material is calculated by mass percentage, ceramic powder 50% to 80%, carbon fiber 10% to 30%, paraffin wax 5% to 15%, polyethylene 1% to 5%, polypropylene 0 to 5%, stearic acid 0.5% to 2%, so that the porous ceramic formula and the high-purity alumina powder granulation powder shrink in the same way during the sintering process, and they are co-formed by dry pressing-isostatic pressing. After sintering, an alumina vacuum ceramic suction cup with a porous ceramic firmly bonded to the substrate can be obtained.

[0027] (3) The preparation method of the present invention introduces hot air during the molten deposition molding process, that is, uses hot air to preheat and soften the solidified layer, thereby reducing the temperature difference between the solidified layer and the molten layer to reduce thermal stress, which can further improve the bonding strength between the layers of the porous ceramic body. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a printing path diagram of 3D printing during the preparation process of the alumina vacuum ceramic suction cup in Examples 1 to 3 of the present invention.

[0029] Figure 2 This is a microscopic morphology of the alumina vacuum ceramic chuck prepared in Example 3. DETAILED DESCRIPTION

[0030] The present invention is further described below in conjunction with the accompanying drawings and specific preferred embodiments, but the protection scope of the present invention is not limited thereby. The materials and instruments used in the following embodiments are all commercially available.

[0031] Embodiment 1:

[0032] A method for preparing an alumina vacuum ceramic chuck of the present invention comprises the following steps:

[0033] (1) Weigh 4000g of alumina powder, 2000g of carbon fiber, 120g of silicon dioxide, 80g of calcium oxide, 40g of magnesium oxide, 600g of paraffin wax, 200g of polyethylene, 50g of polypropylene, and 50g of stearic acid, and mix the raw materials in an internal mixer at a mixing temperature of 180°C for 3 hours. After cooling, a block feed is obtained. In this step, the particle size of the alumina powder is 800 mesh, and the diameter of the carbon fiber is 5μm to 8μm and the length is 2mm to 5mm.

[0034] (2) Using a jaw crusher to crush the block feed obtained in step (1), sieving, and obtaining a granular printing feed; wherein the particle size of the printing feed is less than 5 mm.

[0035] (3) Add the printing feed obtained in step (2) into the FDM 3D printer hopper, import the printing model, and use screw extrusion to perform 3D printing to obtain a printed body; wherein, hot air is introduced during the fused deposition modeling process, and the process parameters of fused deposition modeling (FDM) are: extrusion temperature of 170°C, hot bed temperature of 60°C, hot air temperature of 140°C, hot air pressure of 0.1 Bar, and printing speed of 20 mm / s; the printing path is as follows Figure 1 As shown, the printing direction of each layer is consistent and they are stacked layer by layer.

[0036] (4) The printed body obtained in step (3) is placed in an oven for baking at a temperature of 60° C. for 1 h to eliminate stress. After cooling, the printed body is taken out of the oven to obtain a baked printed body.

[0037] (5) Using a wire cutting machine, the baked printed body obtained in step (4) is cut into thin sheets in a direction perpendicular to the printing path to obtain a sheet-like body; wherein the thickness of the sheet-like body is 5 mm.

[0038] (6) The sheet-like body obtained in step (5) is placed in kerosene for solvent degreasing at a temperature of 40° C. for 24 hours to remove the paraffin in the ceramic body and obtain a porous ceramic body.

[0039] (7) The porous ceramic body obtained in step (6) is placed in a dry pressing mold, and then high-purity alumina powder granulation powder is used to cover the surface of the porous ceramic body and fill the mold, and dry pressing is performed at a pressure of 30 MPa to obtain a dry pressed body; wherein the purity of the alumina powder is 99.6%.

[0040] (8) The dry pressed green body obtained in step (7) is sealed and packaged with a sealing tape, and is placed in an isostatic press for isostatic pressing at a pressure of 150 MPa and a holding time of 20 min to obtain an isostatically pressed green body.

[0041] (9) The isostatically pressed green body obtained in step (8) is placed in a sintering furnace and subjected to pressureless sintering in an air atmosphere, i.e., the temperature is increased to 1600° C. at a heating rate of 0.2° C. / min, and the temperature is kept at this temperature for 3 h. The green body is finely processed using a high-precision CNC machining center to obtain an alumina vacuum ceramic suction cup.

[0042] Embodiment 2:

[0043] A method for preparing an alumina vacuum ceramic chuck of the present invention comprises the following steps:

[0044] (1) Weigh 2000g of alumina powder, 1000g of carbon fiber, 55g of silicon dioxide, 40g of calcium oxide, 18g of magnesium oxide, 315g of paraffin wax, 105g of polyethylene, 30g of polypropylene and 40g of stearic acid, and mix the raw materials in an internal mixer at a mixing temperature of 180°C for 3 hours, and obtain a bulk feed after cooling. In this step, the particle size of the alumina powder is 1200 mesh, and the diameter of the carbon fiber is 5μm to 8μm and the length is 2mm to 5mm.

[0045] (2) Using a jaw crusher to crush the block feed obtained in step (1), sieving, and obtaining a granular printing feed; wherein the particle size of the printing feed is less than 5 mm.

[0046] (3) Add the printing feed obtained in step (2) into the FDM 3D printer hopper, import the printing model, and use screw extrusion to perform 3D printing to obtain a printed blank; wherein the process parameters of fused deposition modeling (FDM) are: extrusion temperature of 175°C, hot bed temperature of 60°C, hot air temperature of 130°C, hot air pressure of 0.15 Bar, printing speed of 25 mm / s, and printing path of Figure 1 As shown, the printing direction of each layer is consistent and they are stacked layer by layer.

[0047] (4) The printed body obtained in step (3) is placed in an oven for baking at a temperature of 65° C. for 1 h to eliminate stress. After cooling, the printed body is taken out of the oven to obtain a baked printed body.

[0048] (5) Using a wire cutting machine, the baked printed body obtained in step (4) is cut into thin sheets in a direction perpendicular to the printing path to obtain a sheet-like body; wherein the thickness of the sheet-like body is 3 mm.

[0049] (6) The sheet-like body obtained in step (5) is placed in kerosene for solvent degreasing at a temperature of 40° C. for 24 hours to remove the paraffin in the ceramic body and obtain a porous ceramic body.

[0050] (7) The porous ceramic body obtained in step (6) is placed in a dry pressing mold, and then high-purity alumina powder granulation powder is used to cover the surface of the porous ceramic body and fill the mold, and dry pressing is performed at a pressure of 30 MPa to obtain a dry pressed body; wherein the purity of the alumina powder is 99.6%.

[0051] (8) The dry pressed green body obtained in step (7) is sealed and packaged with a sealing tape, and is placed in an isostatic press for isostatic pressing at a pressure of 150 MPa and a holding time of 20 min to obtain an isostatically pressed green body.

[0052] (9) The isostatically pressed green body obtained in step (8) is placed in a sintering furnace and sintered in an air atmosphere, i.e., the temperature is increased to 1600° C. at a heating rate of 0.5° C. / min, and the temperature is kept at this temperature for 3 hours. The green body is finely processed using a high-precision CNC machining center to obtain an alumina vacuum ceramic suction cup.

[0053] Embodiment 3:

[0054] A method for preparing an alumina vacuum ceramic chuck of the present invention comprises the following steps:

[0055] (1) Weigh 2000g of alumina powder, 1000g of carbon fiber, 50g of silicon dioxide, 32g of calcium oxide, 18g of magnesium oxide, 350g of paraffin wax, 108g of polyethylene, 54g of polypropylene and 30g of stearic acid and mix them in an internal mixer at a mixing temperature of 180°C for 3 hours. After cooling, a block feed is obtained. In this step, the particle size of the alumina powder is 2000 mesh, and the diameter of the carbon fiber is 5μm to 8μm and the length is 2mm to 5mm.

[0056] (2) Using a jaw crusher to crush the block feed obtained in step (1), sieving, and obtaining a granular printing feed; wherein the particle size of the printing feed is less than 5 mm.

[0057] (3) Add the printing feed obtained in step (2) into the FDM 3D printer hopper, import the printing model, and use screw extrusion to perform 3D printing to obtain a printed body; wherein the process parameters of fused deposition modeling (FDM) are: extrusion temperature of 180°C, hot bed temperature of 70°C, hot air temperature of 130°C, hot air pressure of 0.1 Bar, and printing speed of 20 mm / s; the printing path is equidistant parallel straight lines, such as Figure 1 As shown, the printing direction of each layer is consistent and they are stacked layer by layer.

[0058] (4) The printed body obtained in step (3) is placed in an oven for baking at a temperature of 60° C. for 1 h to eliminate stress. After cooling, the printed body is taken out of the oven to obtain a baked printed body.

[0059] (5) Using a wire cutting machine, the baked printed body obtained in step (4) is cut into thin sheets in a direction perpendicular to the printing path to obtain a sheet-like body; wherein the thickness of the sheet-like body is 5 mm.

[0060] (6) The sheet-like body obtained in step (5) is placed in kerosene for solvent degreasing at a temperature of 40° C. for 24 hours to remove the paraffin in the ceramic body and obtain a porous ceramic body.

[0061] (7) The porous ceramic body obtained in step (6) is placed in a dry pressing mold, and then high-purity alumina powder granulation powder is used to cover the surface of the porous ceramic body and fill the mold, and dry pressing is performed at a pressure of 30 MPa to obtain a dry pressed body; wherein the purity of the alumina powder is 99.6%.

[0062] (8) The dry pressed green body obtained in step (7) is sealed and packaged with a sealing tape, and is placed in an isostatic press for isostatic pressing at a pressure of 150 MPa and a holding time of 20 min to obtain an isostatically pressed green body.

[0063] (9) The isostatically pressed green body obtained in step (8) is placed in a sintering furnace and sintered in an air atmosphere, i.e., the temperature is increased to 1600° C. at a heating rate of 0.2° C. / min, and the temperature is kept at this temperature for 5 hours. The green body is finely processed using a high-precision CNC machining center to obtain an alumina vacuum ceramic suction cup.

[0064] Figure 2 The microscopic morphology of the alumina vacuum ceramic chuck prepared in Example 3. Figure 2 It can be seen that the pore cross-section of the alumina vacuum ceramic suction cup is circular and has a consistent orientation, which is consistent with the shape of the pore-forming agent (carbon fiber), indicating that the present invention achieves directional arrangement of carbon fibers through 3D printing, which is beneficial to the improvement of air flux.

[0065] Comparative Example 1:

[0066] A method for preparing porous alumina ceramics comprises the following steps:

[0067] (1) Weigh 4000g of alumina powder, 2000g of carbon fiber, 120g of silicon dioxide, 80g of calcium oxide, 40g of magnesium oxide, 600g of paraffin wax, 200g of polyethylene, 50g of polypropylene, and 50g of stearic acid, and mix the raw materials in an internal mixer at a mixing temperature of 180°C for 3 hours. After cooling, a block feed is obtained. In this step, the particle size of the alumina powder is 800 mesh, and the diameter of the carbon fiber is 5μm to 8μm and the length is 2mm to 5mm.

[0068] (2) Using a jaw crusher to crush the block feed obtained in step (1), sieving, and obtaining a granular printing feed; wherein the particle size of the printing feed is less than 5 mm.

[0069] (3) Add the printing feed obtained in step (2) into the FDM 3D printer hopper, import the printing model, and use screw extrusion to perform 3D printing to obtain a printed body; wherein the process parameters of fused deposition modeling (FDM) are: extrusion temperature of 170°C, hot bed temperature of 60°C, hot air temperature of 140°C, hot air pressure of 0.1 Bar, and printing speed of 20 mm / s; the printing path is equidistant parallel straight lines, such as Figure 1 As shown, the printing direction of each layer is consistent and they are stacked layer by layer.

[0070] (4) The printed body obtained in step (3) is placed in an oven for baking at a temperature of 60° C. for 1 h to eliminate stress. After cooling, the printed body is taken out of the oven to obtain a baked printed body.

[0071] (5) Using a wire cutting machine, the baked printed body obtained in step (4) is cut into thin sheets in a direction perpendicular to the printing path to obtain a sheet-like body; wherein the thickness of the sheet-like body is 5 mm.

[0072] (6) The sheet-like body obtained in step (5) is placed in kerosene for solvent degreasing at a temperature of 40° C. for 24 hours to remove the paraffin in the ceramic body and obtain a porous ceramic body.

[0073] (7) The porous ceramic body obtained in step (6) is placed in a sintering furnace and sintered in an air atmosphere, i.e., the temperature is increased to 1600° C. at a heating rate of 0.2° C. / min and kept at this temperature for 3 h to obtain a porous alumina ceramic.

[0074] Comparative Example 2:

[0075] A method for preparing porous alumina ceramics comprises the following steps:

[0076] (1) Weigh 4000 g of alumina powder (800 mesh), 2000 g of carbon fiber (diameter 5-8 μm, length 2-5 mm), 120 g of silicon dioxide, 80 g of calcium oxide, and 2000 g of deionized water and place them in a kneader and stir for 3 h to obtain a uniform slurry.

[0077] (2) The clay obtained in step (1) is placed in an oven and baked to obtain porous ceramic powder.

[0078] (3) The porous ceramic powder obtained in step (2) is placed in a kneader, and a 10% polyvinyl alcohol aqueous solution (PVA) having a concentration of 10 wt% is added thereto, and secondary kneading is performed to obtain a porous ceramic powder after secondary kneading.

[0079] (4) placing the porous ceramic powder obtained after secondary kneading in step (3) in a dry pressing mold and performing dry pressing molding at a pressure of 30 MPa to obtain a dry pressed green body.

[0080] (5) The dry-pressed green body obtained in step (4) is sealed and packaged using packaging, and isostatically pressed at a pressure of 150 MPa for a holding time of 20 min to obtain an isostatically pressed green body.

[0081] (6) The isostatically pressed green body obtained in step (5) is placed in an oven for baking, i.e., first baked at 60° C. for 12 h, then baked at 80° C. for 12 h, and after drying, taken out from the oven to obtain a green body.

[0082] (7) Use a wire cutting machine to cut the blank obtained in step (6) transversely into thin sheets with a thickness of 5 mm.

[0083] (8) The flaky green body obtained in step (7) is placed in a sintering furnace, and sintered in an air atmosphere at a heating rate of 0.2°C / min to 1600°C, and kept at this temperature for 3 hours to obtain porous alumina ceramics.

[0084] Comparative Example 3:

[0085] A porous alumina ceramic, the preparation method of which is basically the same as the preparation method of the porous alumina ceramic in Comparative Example 1, the only difference is that in step (1), the carbon fiber is replaced by graphite powder, and the particle size of the graphite powder is 2000 mesh.

[0086] Comparative Example 4:

[0087] A method for preparing an alumina porous ceramic suction cup comprises the following steps:

[0088] (1) Weigh 4000g of alumina powder, 2000g of carbon fiber, 120g of silicon dioxide, 80g of calcium oxide, 40g of magnesium oxide, 600g of paraffin wax, 200g of polyethylene, 50g of polypropylene and 50g of stearic acid and mix them in an internal mixer at a mixing temperature of 180°C for 3 hours. After cooling, a block feed is obtained. In this step, the particle size of the alumina powder is 800 mesh, and the diameter of the carbon fiber is 5μm to 8μm and the length is 2mm to 5mm.

[0089] (2) Using a jaw crusher to crush the block feed obtained in step (1), sieving, and obtaining a granular printing feed; wherein the particle size of the printing feed is less than 5 mm.

[0090] (3) Add the printing feed obtained in step (2) into the FDM 3D printer hopper, import the printing model, and use screw extrusion to perform 3D printing to obtain a printed body; wherein the process parameters of fused deposition modeling (FDM) are: extrusion temperature of 170°C, hot bed temperature of 60°C, hot air temperature of 140°C, hot air pressure of 0.1 Bar, and printing speed of 20 mm / s; the printing path is equidistant parallel straight lines, such as Figure 1 As shown, the printing direction of each layer is consistent and they are stacked layer by layer.

[0091] (4) The printed body obtained in step (3) is placed in an oven for baking at a temperature of 60° C. for 1 h to eliminate stress. After cooling, the printed body is taken out of the oven to obtain a baked printed body.

[0092] (5) Using a wire cutting machine, the baked printed body obtained in step (4) is cut into thin sheets in a direction perpendicular to the printing path to obtain a sheet-like body; wherein the thickness of the sheet-like body is 5 mm.

[0093] (6) The sheet-like body obtained in step (5) is placed in kerosene for solvent degreasing at a temperature of 40° C. for 24 hours to remove the paraffin in the ceramic body and obtain a porous ceramic body.

[0094] (7) The porous ceramic bodies obtained in step (6) are placed in a sintering furnace and sintered in an air atmosphere at a temperature of 1600° C. for 3 h to obtain porous alumina ceramics.

[0095] (8) The high-purity alumina granulated powder is placed in a dry pressing mold and dry pressed at a pressure of 30 MPa to obtain a green body after dry pressing.

[0096] (9) The dry-pressed green body obtained in step (8) is sealed and packaged with a sealing tape, and is placed in an isostatic press for isostatic pressing at a pressure of 150 MPa and a holding time of 20 min to obtain an isostatically pressed green body.

[0097] (10) The isostatically pressed green body obtained in step (9) is placed in a sintering furnace and sintered in an air atmosphere at a temperature of 1600° C. for 3 h. A high-precision CNC machining center is used for fine processing to obtain an alumina ceramic matrix.

[0098] (11) The alumina ceramic substrate obtained in step (10) and the alumina porous ceramic obtained in step (7) are bonded together using sealing glass to obtain an alumina porous ceramic suction cup.

[0099] The porosity of porous ceramics was tested by Archimedes drainage method, the gas flux of porous ceramics was tested by bubble pressure membrane pore size analyzer, the test condition was 0.8 Bar, and the bending strength between porous ceramics and substrate was tested by universal testing machine. The results are shown in Table 1.

[0100] Table 1 Performance data of alumina vacuum ceramic chucks in Examples 1-3, alumina porous ceramics in Comparative Examples 1-3, and alumina porous ceramic chucks in Comparative Example 4

[0101]

[0102] As can be seen from Table 1, the porosity of the alumina vacuum ceramic suction cups prepared in Examples 1-3, the alumina porous ceramics prepared in Comparative Examples 1-3, and the alumina porous ceramic suction cups prepared in Comparative Example 4 are all between 37% and 40%, with no significant difference; however, the alumina porous ceramics prepared in Comparative Examples 1-3 are all separate porous ceramics, and there is no bending strength of the bonding surface. Under similar porosity conditions, the air flux of the alumina porous ceramics prepared in Comparative Example 1 is significantly higher than that of the alumina porous ceramics prepared in Comparative Examples 2 and 3, which indicates that: compared with the porous ceramics prepared by the conventional method, the air flux of the alumina porous ceramics prepared by the preparation method of the present invention is significantly improved, which will be beneficial to the subsequent preparation of alumina vacuum ceramic suction cups. In addition, by comparing the performance data of the alumina vacuum ceramic suction cups prepared in Examples 1-3 and the alumina porous ceramic suction cups prepared in Comparative Example 4, it can be found that compared with the traditional sealing glass bonding method, the one-time molding co-sintering method adopted in the present invention can significantly improve the bonding strength between the porous ceramic and the substrate, so that it can be applied to more demanding environments and improve high-temperature dimensional stability. In summary, the alumina vacuum ceramic suction cup of the present invention has the advantages of high bonding strength, large air flux, and excellent high-temperature dimensional stability.

[0103] The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as above in the preferred embodiment, it is not used to limit the present invention. Any technician familiar with the art can make many possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent replacement, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention, still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for preparing an alumina vacuum ceramic chuck, characterized in that: The following steps are involved: S1, mixing ceramic powder, carbon fiber, paraffin, polyethylene, polypropylene and stearic acid, crushing and sieving to obtain feed; S2, performing FDM 3D printing on the feed obtained in step S1, and baking the feed to obtain a printed body; wherein the printing direction of each layer of the FDM 3D printing is consistent, and each layer is stacked layer by layer; S3, cutting the printed blank obtained in step S2 into sheets to obtain a sheet blank; the cutting direction is a direction perpendicular to the printing path; S4, performing solvent degreasing on the sheet-like body obtained in step S3 to obtain a porous ceramic body; S5, covering the surface of the porous ceramic body obtained in step S4 with granulated powder, and performing dry pressing to obtain a dry pressed body; the granulated powder is alumina powder; S6, isostatically pressing the dry pressed green body obtained in step S5 to obtain an isostatically pressed green body; S7, sintering the isostatically pressed green body obtained in step S6 to obtain an alumina vacuum ceramic suction cup.

2. The method for preparing an alumina vacuum ceramic chuck according to claim 1, characterized in that: In step S1, the added amount of each raw material is calculated by mass percentage, ceramic powder 50% to 80%, carbon fiber 10% to 30%, paraffin 5% to 15%, polyethylene 1% to 5%, polypropylene 0 to 5%, and stearic acid 0.5% to 2%.

3. The method for preparing an alumina vacuum ceramic chuck according to claim 2, characterized in that: In step S1, the ceramic powder includes alumina powder and a sintering aid, the mass percentage of the sintering aid in the ceramic powder is 1% to 10%, the sintering aid is at least one of silicon dioxide, calcium oxide, magnesium oxide and titanium oxide, the diameter of the carbon fiber is 5μm to 8μm, the length of the carbon fiber is 1mm to 5mm, and the particle size of the alumina powder is 500 mesh to 2000 mesh.

4. The method for preparing an alumina vacuum ceramic chuck according to any one of claims 1 to 3, characterized in that: In step S5, the pressure of the dry pressing is 30 MPa to 50 MPa, and the purity of the alumina powder is greater than 99.5%.

5. The method for preparing an alumina vacuum ceramic chuck according to any one of claims 1 to 3, characterized in that: In step S6, the pressure of the isostatic pressing is 150 MPa to 200 MPa, and the holding time of the isostatic pressing is 10 min to 30 min.

6. The method for preparing an alumina vacuum ceramic chuck according to any one of claims 1 to 3, characterized in that: In step S7, the sintering temperature is 1550°C to 1650°C, the sintering time is 2h to 5h, the heating rate during the sintering process is 0.1°C / min to 4°C / min, and the sintering is performed under air conditions.

7. The method for preparing an alumina vacuum ceramic chuck according to any one of claims 1 to 3, characterized in that: In step S1, the mixing temperature is 140°C to 200°C, the mixing time is 2h to 4h, and the particle size of the feed is less than 5mm.

8. The method for preparing an alumina vacuum ceramic chuck according to any one of claims 1 to 3, characterized in that: In step S2, the molding method of the FDM3D printing is fused deposition molding, and the process parameters of the fused deposition molding are: extrusion temperature 160℃~200℃, hot bed temperature 60℃~100℃, printing speed 10mm / s~30mm / s; hot air is introduced during the fused deposition molding process, and the process parameters of the hot air are: hot air temperature 100℃~150℃, hot air pressure 0.1Bar~0.5Bar; the baking temperature is 60℃~120℃, and the baking time is 0.5h~2h.

9. The method for preparing an alumina vacuum ceramic chuck according to any one of claims 1 to 3, characterized in that: In step S3, the thickness of the sheet blank is 2 mm to 20 mm; In step S4, the specific process of the solvent degreasing is: immersing the sheet-like green body obtained in step S3 in kerosene; the immersion temperature is 30° C. to 60° C., and the immersion time is 16 h to 48 h.

10. An alumina vacuum ceramic chuck prepared by the preparation method according to any one of claims 1 to 9.

Images