CN116675520A - Preparation method of 7-13um particle size calcined alpha alumina powder and high-density ceramic - Google Patents
Preparation method of 7-13um particle size calcined alpha alumina powder and high-density ceramic Download PDFInfo
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- 239000000919 ceramic Substances 0.000 title claims abstract description 95
- 239000000843 powder Substances 0.000 title claims abstract description 88
- 239000002245 particle Substances 0.000 title claims abstract description 68
- PNEYBMLMFCGWSK-UHFFFAOYSA-N Alumina Chemical compound [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 title claims abstract description 61
- 238000002360 preparation method Methods 0.000 title claims abstract description 13
- 238000000227 grinding Methods 0.000 claims abstract description 49
- 238000005245 sintering Methods 0.000 claims abstract description 32
- 238000002156 mixing Methods 0.000 claims abstract description 31
- 239000007787 solid Substances 0.000 claims abstract description 25
- 239000011268 mixed slurry Substances 0.000 claims abstract description 24
- 238000000034 method Methods 0.000 claims abstract description 21
- 239000000463 material Substances 0.000 claims abstract description 17
- 238000000462 isostatic pressing Methods 0.000 claims abstract description 10
- 238000007599 discharging Methods 0.000 claims abstract description 7
- 239000003292 glue Substances 0.000 claims abstract description 7
- 239000008187 granular material Substances 0.000 claims abstract description 4
- 238000003825 pressing Methods 0.000 claims abstract description 4
- 238000004321 preservation Methods 0.000 claims abstract description 3
- 238000010345 tape casting Methods 0.000 claims abstract description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 25
- 238000005469 granulation Methods 0.000 claims description 17
- 230000003179 granulation Effects 0.000 claims description 17
- 239000002002 slurry Substances 0.000 claims description 13
- 239000007921 spray Substances 0.000 claims description 12
- 239000004372 Polyvinyl alcohol Substances 0.000 claims description 10
- 229920002451 polyvinyl alcohol Polymers 0.000 claims description 10
- 238000001238 wet grinding Methods 0.000 claims description 10
- 238000005266 casting Methods 0.000 claims description 7
- 229920000604 Polyethylene Glycol 200 Polymers 0.000 claims description 6
- 239000004014 plasticizer Substances 0.000 claims description 6
- 238000004519 manufacturing process Methods 0.000 claims description 4
- 238000009826 distribution Methods 0.000 claims description 3
- TZCXTZWJZNENPQ-UHFFFAOYSA-L barium sulfate Chemical compound [Ba+2].[O-]S([O-])(=O)=O TZCXTZWJZNENPQ-UHFFFAOYSA-L 0.000 description 10
- 238000001035 drying Methods 0.000 description 8
- 230000015556 catabolic process Effects 0.000 description 7
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 6
- 239000011230 binding agent Substances 0.000 description 6
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 6
- RVTZCBVAJQQJTK-UHFFFAOYSA-N oxygen(2-);zirconium(4+) Chemical compound [O-2].[O-2].[Zr+4] RVTZCBVAJQQJTK-UHFFFAOYSA-N 0.000 description 6
- 229910001928 zirconium oxide Inorganic materials 0.000 description 6
- 239000005995 Aluminium silicate Substances 0.000 description 5
- 235000012211 aluminium silicate Nutrition 0.000 description 5
- NLYAJNPCOHFWQQ-UHFFFAOYSA-N kaolin Chemical compound O.O.O=[Al]O[Si](=O)O[Si](=O)O[Al]=O NLYAJNPCOHFWQQ-UHFFFAOYSA-N 0.000 description 5
- 239000000395 magnesium oxide Substances 0.000 description 5
- 235000012245 magnesium oxide Nutrition 0.000 description 5
- 239000011812 mixed powder Substances 0.000 description 5
- 239000003973 paint Substances 0.000 description 5
- 239000004576 sand Substances 0.000 description 5
- 239000000454 talc Substances 0.000 description 5
- 229910052623 talc Inorganic materials 0.000 description 5
- 235000012222 talc Nutrition 0.000 description 5
- 239000011324 bead Substances 0.000 description 4
- 238000011049 filling Methods 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 description 4
- 229920002635 polyurethane Polymers 0.000 description 4
- 239000004814 polyurethane Substances 0.000 description 4
- 230000007547 defect Effects 0.000 description 3
- 238000010292 electrical insulation Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000013001 point bending Methods 0.000 description 2
- 230000001105 regulatory effect Effects 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- 238000005303 weighing Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000011068 loading method Methods 0.000 description 1
- 229910052573 porcelain Inorganic materials 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 238000004537 pulping Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
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- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
- C04B35/10—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on aluminium oxide
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Abstract
The invention discloses a preparation method of calcined alpha alumina powder with particle size of 7-13um and high-density ceramic, which comprises the following steps: adding sintering aid into calcined alpha alumina powder with particle size of 1.5-2.5um, and preparing into raw ceramic chip with particle size of 0.5-1mm by tape casting process; and (3) discharging glue from the green ceramic chip, sintering the green ceramic chip into thin ceramic chips, and grinding the ceramic chips to obtain calcined alpha alumina powder with the particle size of 7-13 um. Mixing 7-13um and calcined alpha alumina powder with the particle size of 1.5-2.5um according to the mass ratio of (2-8) to obtain mixed slurry; granulating the prepared mixed slurry to form granules; pressing the pelleting material into a solid blank by using an isostatic pressing mode; and (3) the solid blank is subjected to heat preservation at 1650+/-10 ℃ for 2 hours, and the insulating ceramic is obtained. The method can conveniently and rapidly prepare the calcined alpha alumina powder with the particle size of 7-13um, and obtain the ceramic with high density.
Description
Technical Field
The invention belongs to the field of alumina ceramics, and relates to a preparation method of 7-13um particle size calcined alpha alumina powder and high-density ceramics.
Background
The average grain size of the calcined alpha alumina powder adopted by the 95 alumina ceramic vacuum tube is generally between 1.5 and 2.5um, and the grain distribution is concentrated, so that the problems of lower density of a blank pressed by an isostatic pressing process, poor strength, low sintering density of a ceramic part, serious attenuation of electrical insulation performance along with the increase of the thickness of the ceramic part and the like are caused.
Particle size grading is an effective method for solving the problem of low density of the molded blank. Experience with particle size grading generally requires that the two particle sizes differ by a factor of 4 to 5, so that for calcined alpha alumina powder of 1.5 to 2.5um, alumina grains of between 0.3 and 0.6um or between 7 and 13um are required to form a more desirable grading. However, for alpha alumina, the powder with particle size between 0.3 and 0.6um, the alpha conversion rate cannot reach more than 96% required for preparing 95 alumina ceramic, and in addition, too fine powder is easy to agglomerate and difficult to disperse in the slurry preparation process. Powder with the granularity of 7-13um is difficult to obtain by the existing calcination mode of the traditional alpha alumina. Even if the powder with the particle size is prepared by adopting plasma sintering and other modes, the 95 alumina ceramic with high performance is difficult to sinter at ordinary temperature because of low powder activity.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a preparation method of 7-13um particle size calcined alpha alumina powder and high-density ceramic, which can conveniently and rapidly prepare the 7-13um particle size calcined alpha alumina powder.
In order to achieve the purpose, the invention is realized by adopting the following technical scheme:
the preparation method of the calcined alpha alumina powder with the particle size of 7-13um comprises the following steps:
adding sintering aid into calcined alpha alumina powder with particle size of 1.5-2.5um, and preparing into raw ceramic chip with particle size of 0.5-1mm by tape casting process;
and (3) discharging glue from the green ceramic chip, sintering the green ceramic chip into thin ceramic chips, and grinding the ceramic chips to obtain calcined alpha alumina powder with the particle size of 7-13 um.
Preferably, the casting process comprises the following steps:
adding sintering aid accounting for 5% of the mass of calcined alpha alumina powder with the particle size of 1.5-2.5um into the calcined alpha alumina powder, grinding the powder for 4-5 hours, adding PVA1788 accounting for 1-5% and plasticizer PEG200 accounting for 0.3-0.5% into the powder after grinding is finished, and continuously mixing for 12 hours; after the mixing is finished, the height of a scraper is adjusted to be 0.2-0.6mm, a green ceramic chip with the thickness of 0.5-1mm is cast, the green ceramic chip is dried at 120 ℃, the temperature is increased to fracture the green ceramic chip, the dried ceramic chip is subjected to glue discharging at 200-500 ℃, and then the ceramic chip is sintered at 1400-1600 ℃ to obtain the sheet ceramic with the thickness of 0.5-1 mm.
Further, the grinding process is wet grinding, and water is added to form grinding slurry, wherein the solid content of the grinding slurry is 50-60%.
The preparation method of the high-density ceramic comprises the following steps:
s1, mixing the 7-13um particle size calcined alpha alumina powder and 1.5-2.5um particle size calcined alpha alumina powder according to the mass ratio of (2-8) to obtain mixed slurry;
s2, granulating the prepared mixed slurry to form granules;
s3, pressing the granulating material into a solid blank by using an isostatic pressing mode;
and S4, the solid blank is subjected to heat preservation at 1650+/-10 ℃ for 2 hours, and the insulating ceramic is obtained.
Preferably, the mixing is completed by adding 0.5-2% of polyvinyl alcohol and 5% of sintering aid relative to the total mass of the two powders to form a mixed slurry, and the solid content of the mixed slurry is 50-60%, and the mixed slurry is mixed for 1 hour.
Further, PVA1788 or PVA1799 is used as the polyvinyl alcohol.
Preferably, the three-cup viscosity of the mixed slurry is 20-30s after the mixing is completed.
Preferably, the granulation is carried out by using a spray granulation tower, the outlet temperature of the spray granulation tower is set to be 90-100 ℃, the inlet temperature of the spray granulation tower is set to be 230-260 ℃, the granularity distribution of the granulation material is 60-300 meshes, and the water content is 0.3-0.5%.
Preferably, the isostatic pressure is 120MPa.
Preferably, after being pressed into a blank, the blank is turned into a round bar, and after being kept at the temperature of 60 ℃ for 2 hours in an oven, the blank is sintered.
Compared with the prior art, the invention has the following beneficial effects:
the invention prepares the calcined alpha alumina powder and the sintering aid into the raw ceramic chip with the thickness of 0.5-1mm by adopting a casting process, and then the raw ceramic chip is subjected to glue discharging and sintering to form the flake ceramic, and then the flake ceramic is ground to the particle size of 7-13um, so that the ceramic can be obtained by adopting the existing ceramic to carry out the casting process and grinding, the raw material is convenient to obtain, the cost is lower, and the preparation is convenient and quick.
Furthermore, the calcined alpha alumina powder with the particle size of 7-13um can be obtained by adopting waste products and waste porcelain, so that the cost is greatly reduced, and the green sustainable production is realized.
According to the invention, the calcined alpha alumina powder with the particle size of 7-13um and the calcined alpha alumina powder with the particle size of 1.5-2.5um are graded according to a proportion to obtain ideal graded powder, and then the ceramic with high density and good electrical insulation performance is obtained through pulping, granulating, isostatic pressing and sintering.
Drawings
FIG. 1 is a three-point bending test strength chart of a blank of the present invention;
FIG. 2 is a graph of density of different large particle size fractions of insulating ceramics according to the present invention;
fig. 3 is a graph of the dielectric strength of the dielectric ceramic of the present invention at the same power frequency.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the invention; all other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
It should be noted that the words "front", "rear", "left", "right", "upper" and "lower" used in the following description refer to directions in the drawings, and the words "inner" and "outer" refer to directions toward or away from, respectively, the geometric center of a particular component.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.
The preparation method of the calcined alpha alumina powder with the particle size of 7-13um comprises the following steps:
1) Calcined alpha alumina powder with the grain size of 1.5-2.5um is selected, and a sintering aid accounting for 5% of the mass of the calcined alpha alumina powder is added, wherein the sintering aid is kaolin, magnesium oxide, talcum, barium sulfate, zirconium oxide and the like.
2) Grinding the powder in a star ball mill for 4-5 hours, wherein the grinding process is wet grinding by adding water, grinding slurry is formed after adding water in the wet grinding, the solid content of the grinding slurry is 50-60%, PVA1788 with the solid content of 1-5% and plasticizer PEG200 with the solid content of 0.3-0.5% are added after grinding is finished, and mixing is continued for 12 hours.
3) After mixing is completed, the viscosity is tested using a three-cup paint, the viscosity is required to be 25-35s, otherwise, water is added proportionally to adjust the viscosity until the viscosity is within the required range. The height of the scraper is regulated to be 0.2-0.6mm, and the green ceramic tile with the thickness of 0.5-1mm is cast.
4) Drying at 120 ℃, and rapidly heating to 120-150 ℃ in an oven to crack the raw ceramic chips.
5) And discharging glue from the dried ceramic chip at 200-500 ℃, and sintering at 1400-1600 ℃.
6) And (3) cleaning the sintered flake ceramic, and then placing the flake ceramic into a sand mill, and adopting zirconia beads with the diameter of 1-2mm for unidirectional non-circulating grinding. The particle size test was performed every 1 grinding, and the grinding was stopped until the average particle size was 7-13 um. And then, drying the ground powder for later use.
In the prepared calcined alpha alumina powder with the particle size of 7-13um, single particles are formed by agglomerating a plurality of calcined alpha alumina powder with the particle size of 1.5-2.5 mm.
The preparation method of the high-density ceramic comprises the following steps:
1) Mixing the above-mentioned 7-13um particle size calcined alpha alumina powder and 1.5-2.5mm particle size calcined alpha alumina powder according to the mass ratio of (2-8), and mixing in ball mill for 4-5 hr.
And (3) adding 0.5-2% of polyvinyl alcohol (PVA 1788 or PVA 1799) and 5% of sintering aid relative to the total mass of the two powder materials to form mixed slurry after mixing, wherein the solid content of the mixed slurry is 50-60%, and mixing is carried out for 1 hour.
Wherein, the sintering aid uses kaolin, magnesia, talcum, barium sulfate, zirconia and the like; 0.5-2% of polyvinyl alcohol refers to the mass fraction of the dry powder of the polyvinyl alcohol relative to the dry powder of the mixed powder; the polyvinyl alcohol is added by dissolving dry powder in water solution to prepare solution, and the concentration of the solution is 5-10%.
After mixing is completed, the viscosity is tested using a three-cup paint, the viscosity is required to be 20-30s, otherwise, water is added proportionally to adjust the viscosity until the viscosity is within the required range.
2) And granulating the prepared mixed slurry by using a spray granulation tower.
Wherein, the outlet temperature of the spray granulation tower is set to be 90-100 ℃, the inlet temperature of the spray granulation tower is set to be 230-260 ℃, the granulation materials are formed, the granularity of the granulation materials is distributed between 60-300 meshes, and the water content is 0.3-0.5%.
3) And pressing into a cylindrical solid blank by using an isostatic pressing mode.
Filling the granulating material into a polyurethane tool with the diameter phi 40 and the height 200mm, and performing isostatic pressing to obtain a solid round bar by using 120MPa pressure.
4) The pressed blank was turned into a phi 20 regular round bar by a precision lathe, the density of the blank was tested, and then the three-point bending strength test was performed after keeping the temperature in an oven at 60 ℃ for 2 hours, as shown in fig. 1.
As the addition ratio of the large particle powder (sand mill grind powder, average particle diameter 10 um) increases, the density of the pressed blank increases significantly at the same pressure, accompanied by an increase in the green body strength. When the large-particle powder accounts for 70% of the mixed powder, the density of the blank reaches 2.6g/cm < 3 >, and the strength of the blank reaches more than 3 MPa. It can be seen that the large particle powder with the average particle size of 10um and the calcined alpha alumina powder with the average particle size of 1.5-2um form grading, thereby improving the density and strength of the green body.
5) And (5) blank sintering.
The blank is sintered at 1650+ -10deg.C for 2 hours.
Wherein the ceramic body sintered density increases with the density of the ceramic as the ratio of the large particles increases.
As shown in fig. 2, with the introduction of the large particle powder, the density of the ceramic increases with the increase of the large particle ratio after sintering the blank at 1650 ℃. The introduction of large-particle powder improves the density of the ceramic blank, thereby promoting the compactness of ceramic sintering.
Industrial frequency withstand voltage of different grain composition.
As shown in fig. 3, under the same power frequency condition, the breakdown field strength of the ceramic is obviously reduced along with the increase of the thickness of the ceramic. When the thickness of the ceramic is 0.5mm, the proportion relation between the breakdown field intensity of the ceramic and the mixed powder is not large, but with the increase of the thickness of the ceramic, the proportion between the breakdown field intensity and the mixed powder has an obvious relation: the ceramic breakdown field intensity is increased by increasing the proportion of large-particle powder. This is because the breakdown field strength of the ceramic is closely related to defects inside the ceramic, the thickness of the ceramic increases, and defects inside the ceramic increase, resulting in a decrease in the breakdown field strength. The introduction of large-particle powder can well improve the compactness of the ceramic, so that the phenomenon that the breakdown field intensity is increased along with the increase of the proportion of large particles to mixed powder is shown when the thickness of the ceramic is increased.
The sintered 95 alumina ceramic is ground and crushed to obtain proper graded calcined alpha alumina powder with required particle size, so as to prepare a graded high-density green body and obtain ceramic with high density and high insulating field strength.
Example 1:
1) Calcined alpha alumina powder with the grain size of 1.5-2.5um is selected, 5% of sintering aid is added, and kaolin, magnesium oxide, talcum, barium sulfate and zirconium oxide are used as the sintering aid.
2) Grinding the powder in a star ball mill for 5 hours, wherein the grinding process is wet grinding by adding water, the wet grinding is carried out by adding water to form grinding slurry, the solid content of the grinding slurry is 60%, 3% of PVA1788 and 0.4% of plasticizer PEG200 are added after the grinding is finished, and the mixing is continued for 12 hours.
3) After mixing is completed, the viscosity is tested using a three-cup paint, the viscosity is required to be 30s, otherwise water is added proportionally to adjust the viscosity until the required range is reached. The height of the scraper is adjusted to be 0.6mm, and the green ceramic chip with the thickness of 1mm is cast.
4) Drying at 120 ℃, and rapidly heating to 120 ℃ in an oven to crack the raw ceramic chips.
5) The dried ceramic chip is discharged at 300 ℃ and sintered at 1600 ℃.
6) And loading the 95 alumina casting ceramic chip with the thickness of 1mm into a 1.5L sand mill, and carrying out unidirectional non-circulating grinding by adopting zirconia beads with the thickness of 1 mm. The particle size test was performed every 1 grinding, until the average particle size was 10um, and the grinding was stopped. And then, drying the ground powder for later use.
7) 8kg of grinding powder, 2kg of calcined alpha alumina powder and auxiliary materials are weighed, and are put into a ball mill to be mixed for 4 hours. The particle size of the calcined alpha alumina powder is required to be 2um.
8) After the completion of the mixing, 1% of a binder PVA1788 solution and 5% of a sintering aid, relative to the total mass of the two powders, were added to form a mixed slurry, the solid content of the mixed slurry was 50%, the concentration of the binder solution was 5%, and the mixed slurry was mixed for 1 hour.
9) After mixing is completed, the viscosity is tested using a three-viscosity-coated cup, the viscosity is required to be 25s, otherwise, water is added proportionally to adjust the viscosity until the requirement is reached.
10 Granulating by using a spray granulation tower, wherein the outlet temperature is set to 95 ℃, the inlet temperature is set to 250 ℃, and the water content of the granulating material is ensured to be 0.4%.
11 Filling the pelleting material into a polyurethane tool with the diameter phi 40 and the height 200, and performing isostatic pressing to obtain a solid round bar by using 120MPa pressure.
12 A round bar is turned into a green body with a regular shape of phi 20.
13 The round bar is sintered at 1650 ℃ for 2 hours to obtain the insulating ceramic.
Example 2:
1) Calcined alpha alumina powder with the grain size of 1.5-2.5um is selected, 5% of sintering aid is added, and kaolin, magnesium oxide, talcum, barium sulfate and zirconium oxide are used as the sintering aid.
2) Grinding the powder in a star ball mill for 4.5 hours, wherein the grinding process is wet grinding by adding water, grinding slurry is formed after adding water in the wet grinding, the solid content of the grinding slurry is between 55 percent, 1 percent of PVA1788 and 0.3 percent of plasticizer PEG200 are added after the grinding is finished, and the mixing is continued for 12 hours.
3) After mixing is complete, the viscosity is tested using a three-cup paint, the viscosity is required to be 25s, otherwise water is added proportionally to adjust the viscosity until it is within the required range. The height of the scraper is adjusted to be 0.4mm, and the green ceramic tile with the thickness of 0.8mm is cast.
4) Drying at 120 ℃, and rapidly heating to 130 ℃ in an oven to crack the raw ceramic chips.
5) The dried ceramic chip is discharged at 200 ℃ and sintered at 1400 ℃.
6) 95 alumina casting ceramic chips with the thickness of 0.8mm are taken to be put into a 1.5L sand mill, and zirconium oxide beads with the thickness of 2mm are adopted to carry out unidirectional non-circulating grinding. The particle size test was performed every 1 grinding, and the grinding was stopped until the average particle size was 13 um. And then, drying the ground powder for later use.
7) Weighing 5kg of grinding powder, 5kg of calcined alpha alumina powder and 5kg of auxiliary materials, and putting into a ball mill to mix for 5 hours. The particle size of the calcined alpha alumina powder is required to be 2.5um.
8) After the completion of the mixing, a binder PVA1799 solution of 2% and a sintering aid of 5% relative to the total mass of the two powders were added to form a mixed slurry, the solid content of the mixed slurry was 55%, the concentration of the binder solution was 5%, and the mixed slurry was further mixed for 1 hour.
9) After mixing is completed, the viscosity is tested using a three-viscosity-coated cup, the viscosity is required to be 30s, otherwise, water is added proportionally to adjust the viscosity until the requirement is met.
10 Granulating by using a spray granulation tower, wherein the outlet temperature is set to be 100 ℃, the inlet temperature is set to be 260 ℃, and the water content of the granulating material is ensured to be 0.5%.
11 Filling the pelleting material into a polyurethane tool with the diameter phi 40 and the height 200, and performing isostatic pressing to obtain a solid round bar by using 120MPa pressure.
12 A round bar is turned into a green body with a regular shape of phi 20.
13 The round bar is sintered at 1660 ℃ for 2 hours to obtain the insulating ceramic.
Example 3:
1) Calcined alpha alumina powder with the grain size of 1.5-2.5um is selected, 5% of sintering aid is added, and kaolin, magnesium oxide, talcum, barium sulfate and zirconium oxide are used as the sintering aid.
2) Grinding the powder in a star ball mill for 4 hours, wherein the grinding process is wet grinding by adding water, the wet grinding is carried out by adding water to form grinding slurry, the solid content of the grinding slurry is 50%, 5% of PVA1788 and 0.5% of plasticizer PEG200 are added after the grinding is finished, and the mixing is continued for 12 hours.
3) After mixing is completed, the viscosity is tested using a three-cup paint, the viscosity is required to be 35s, otherwise water is added proportionally to adjust the viscosity until it is within the required range. The height of the scraper is regulated to be 0.2mm, and the green ceramic tile with the thickness of 0.5mm is cast.
4) Drying at 120 ℃, and rapidly heating to 150 ℃ in an oven to crack the raw ceramic chips.
5) The dried ceramic chip is discharged at 500 ℃ and sintered at 1500 ℃.
6) 95 alumina casting ceramic chips with the thickness of 0.5mm are taken to be put into a 1.5L sand mill, and zirconium oxide beads with the thickness of 1.5mm are adopted to carry out unidirectional non-circulating grinding. The particle size test was performed every 1 grinding, and the grinding was stopped until the average particle size was 7 um. And then, drying the ground powder for later use.
7) Weighing 2kg of grinding powder, 8kg of calcined alpha alumina powder and auxiliary materials, and putting into a ball mill to mix for 4.5 hours. The particle size of the calcined alpha alumina powder is required to be 1.5um.
8) After the completion of the mixing, a binder PVA1788 solution in an amount of 0.5% relative to the total mass of the two powders and a sintering aid in an amount of 5% were added to form a mixed slurry, the solid content of the mixed slurry was 60%, the concentration of the binder solution was 5%, and the mixture was further mixed for 1 hour.
9) After mixing is completed, the viscosity is tested using a three-viscosity-coated cup, the viscosity is required to be 20, otherwise, water is added proportionally to adjust the viscosity until the requirement is reached.
10 Granulating by using a spray granulation tower, wherein the outlet temperature is set to be 90-100 ℃, the inlet temperature is set to be 230-260 ℃, and the water content of the granulating material is ensured to be 0.3%.
11 Filling the pelleting material into a polyurethane tool with the diameter phi 40 and the height 200, and performing isostatic pressing to obtain a solid round bar by using 120MPa pressure.
12 A round bar is turned into a green body with a regular shape of phi 20.
13 The round bar is sintered at 1640 ℃ for 2 hours to obtain the insulating ceramic.
It is noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
It is to be understood that the above description is intended to be illustrative, and not restrictive. Many embodiments and many applications other than the examples provided will be apparent to those of skill in the art upon reading the above description. The scope of the present teachings should, therefore, be determined not with reference to the above description, but instead should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. The disclosures of all articles and references, including patent applications and publications, are incorporated herein by reference for the purpose of completeness. The omission of any aspect of the subject matter disclosed herein in the preceding claims is not intended to forego such subject matter, nor should the applicant not be considered to be a part of the disclosed subject matter.
Claims (10)
1. The preparation method of the calcined alpha alumina powder with the particle size of 7-13um is characterized by comprising the following steps:
adding sintering aid into calcined alpha alumina powder with particle size of 1.5-2.5um, and preparing into raw ceramic chip with particle size of 0.5-1mm by tape casting process;
and (3) discharging glue from the green ceramic chip, sintering the green ceramic chip into thin ceramic chips, and grinding the ceramic chips to obtain calcined alpha alumina powder with the particle size of 7-13 um.
2. The method for preparing calcined α alumina powder of 7-13um particle size according to claim 1, wherein the casting process comprises the steps of:
adding sintering aid accounting for 5% of the mass of calcined alpha alumina powder with the particle size of 1.5-2.5um into the calcined alpha alumina powder, grinding the powder for 4-5 hours, adding PVA1788 accounting for 1-5% and plasticizer PEG200 accounting for 0.3-0.5% into the powder after grinding is finished, and continuously mixing for 12 hours; after the mixing is finished, the height of a scraper is adjusted to be 0.2-0.6mm, a green ceramic chip with the thickness of 0.5-1mm is cast, the green ceramic chip is dried at 120 ℃, the temperature is increased to fracture the green ceramic chip, the dried ceramic chip is subjected to glue discharging at 200-500 ℃, and then the ceramic chip is sintered at 1400-1600 ℃ to obtain the sheet ceramic with the thickness of 0.5-1 mm.
3. The method for preparing calcined alpha alumina powder with a particle size of 7-13um according to claim 2, wherein the grinding process is wet grinding, and the grinding slurry is formed by adding water, and the solid content of the grinding slurry is 50-60%.
4. The preparation method of the high-density ceramic is characterized by comprising the following steps:
s1, mixing the 7-13um particle size calcined alpha alumina powder in any one of claims 1-3 with 1.5-2.5um particle size calcined alpha alumina powder according to the mass ratio of (2-8) to obtain mixed slurry;
s2, granulating the prepared mixed slurry to form granules;
s3, pressing the granulating material into a solid blank by using an isostatic pressing mode;
and S4, the solid blank is subjected to heat preservation at 1650+/-10 ℃ for 2 hours, and the insulating ceramic is obtained.
5. The method of producing a high-density ceramic according to claim 4, wherein the mixing is completed by adding 0.5 to 2% of polyvinyl alcohol and 5% of a sintering aid relative to the total mass of the two powders to form a mixed slurry, and the solid content of the mixed slurry is 50 to 60%, and mixing is further carried out for 1 hour.
6. The method for producing a high-density ceramic according to claim 5, wherein the polyvinyl alcohol is PVA1788 or PVA1799.
7. The method of producing a high-density ceramic according to claim 4, wherein the three-cup viscosity of the mixed slurry is 20 to 30 seconds after the completion of the mixing.
8. The method for producing high-density ceramics according to claim 4, wherein the granulation is carried out by using a spray granulation tower, the outlet temperature of the spray granulation tower is set to 90-100 ℃, the inlet temperature of the spray granulation tower is set to 230-260 ℃, the grain size distribution of the granulated material is 60-300 meshes, and the water content is 0.3-0.5%.
9. The method for producing a high-density ceramic according to claim 4, wherein the isostatic pressure is 120MPa.
10. The method of producing a high-density ceramic according to claim 4, wherein the blank is turned into a round bar after being pressed, and the round bar is sintered after being kept at a constant temperature of 60 ℃ for 2 hours in an oven.
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Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101525231A (en) * | 2008-03-05 | 2009-09-09 | 邹平金刚新材料有限公司 | Process or preparing microcrystal wear-resisting alumina ceramic |
| CN102503378A (en) * | 2011-10-14 | 2012-06-20 | 吕佳佳 | Thin chip ceramic substrate and manufacturing method thereof |
| CN103553575A (en) * | 2013-10-22 | 2014-02-05 | 襄阳市金控特种陶瓷科技有限公司 | Ceramic raw material obtained by spherically calcining powder |
| CN105819833A (en) * | 2015-01-04 | 2016-08-03 | 郑州金阳光陶瓷有限公司 | Preparation method of self-sharpening microcrystalline alumina ceramic abrasive particles |
| CN107034379A (en) * | 2017-04-07 | 2017-08-11 | 西安明科微电子材料有限公司 | A kind of preparation method of high-volume fractional oxidation aluminium ceramics enhancing aluminium composite material |
| CN108947504A (en) * | 2018-08-29 | 2018-12-07 | 厦门朝瓷科技有限公司 | Submicrometer structure ultrathin alumina ceramic substrate and preparation method |
| CN111004020A (en) * | 2019-12-26 | 2020-04-14 | 淄博奥诺新材料科技有限公司 | Method for preparing high-purity alumina ceramic substrate at low temperature |
| CN115650708A (en) * | 2022-11-15 | 2023-01-31 | 江苏省陶瓷研究所有限公司 | High-dielectric-strength 95 aluminum oxide ceramic material and preparation method thereof |
-
2023
- 2023-06-12 CN CN202310693475.2A patent/CN116675520A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101525231A (en) * | 2008-03-05 | 2009-09-09 | 邹平金刚新材料有限公司 | Process or preparing microcrystal wear-resisting alumina ceramic |
| CN102503378A (en) * | 2011-10-14 | 2012-06-20 | 吕佳佳 | Thin chip ceramic substrate and manufacturing method thereof |
| CN103553575A (en) * | 2013-10-22 | 2014-02-05 | 襄阳市金控特种陶瓷科技有限公司 | Ceramic raw material obtained by spherically calcining powder |
| CN105819833A (en) * | 2015-01-04 | 2016-08-03 | 郑州金阳光陶瓷有限公司 | Preparation method of self-sharpening microcrystalline alumina ceramic abrasive particles |
| CN107034379A (en) * | 2017-04-07 | 2017-08-11 | 西安明科微电子材料有限公司 | A kind of preparation method of high-volume fractional oxidation aluminium ceramics enhancing aluminium composite material |
| CN108947504A (en) * | 2018-08-29 | 2018-12-07 | 厦门朝瓷科技有限公司 | Submicrometer structure ultrathin alumina ceramic substrate and preparation method |
| CN111004020A (en) * | 2019-12-26 | 2020-04-14 | 淄博奥诺新材料科技有限公司 | Method for preparing high-purity alumina ceramic substrate at low temperature |
| CN115650708A (en) * | 2022-11-15 | 2023-01-31 | 江苏省陶瓷研究所有限公司 | High-dielectric-strength 95 aluminum oxide ceramic material and preparation method thereof |
Non-Patent Citations (2)
| Title |
|---|
| 师琳璞;赵延飞;薛建强;张秀勤;: "粒径及成型压力对α氧化铝粉体烧结行为的影响", 材料开发与应用, no. 01, 15 February 2020 (2020-02-15) * |
| 李晓东;周文孝;杨东亮;殷书建;: "影响特种陶瓷干压成形坯体致密度的因素", 山东陶瓷, no. 02, 25 April 2010 (2010-04-25) * |
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