Preparation method of high-aluminum ceramic and high-aluminum ceramic

Abstract

The invention relates to the technical field of ceramic materials, and provides a preparation method of high-aluminum ceramic and the high-aluminum ceramic, the preparation method comprises the following steps: 1) preparation of ceramic slurry: weighing 6.5-9 kg of small materials, 5-7 kg of deionized water, 22-34 ml of a compound amino acid emulsifying aid and 12-20 ml of an active component, and sequentially adding into a ball mill for primary grinding; weighing 93.5-127 kg of alpha-aluminum oxide powder, 30-40.7 kg of deionized water and 2-3.2 kg of a compound emulsifier, and sequentially adding into the ball mill for secondary grinding to obtain ceramic slurry; 2) spray granulation: spraying the ceramic slurry into a granulation tower for atomization, and rapidly drying the atomized ceramic slurry to obtain ceramic powder; 3) dry pressing: pressing the ceramic powder through a dry press to obtain a blank; and 4) high-temperature sintering: sintering the blank body, naturally cooling, grinding and polishing to obtain a high-aluminum ceramic finished product. Large air holes and the number of the air holes in the high-aluminum ceramic structure are eliminated to a great extent, and various performance indexes are effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of ceramic materials, and in particular to a preparation method of high-aluminum ceramics and the high-aluminum ceramics. Background Art

[0002] High-alumina ceramics, also known as alumina ceramics, have high strength, high hardness, high wear resistance and high corrosion resistance. They are widely used in the field of structural materials in the machinery manufacturing industry and chemical engineering. They can generally be used to make pump parts, bearings, pistons, valves, etc.

[0003] When preparing high-alumina ceramics, a defoaming agent is required to eliminate bubbles and uneven mixing of pseudo-particles. The existing defoaming agent is generally composed of an active ingredient with a single function, an emulsifier, a carrier and an emulsifying aid. The ratio of each component, the interval time of addition, the order of addition, etc. will affect the production quality of high-alumina ceramics. The precision requirements are high and the production difficulty is relatively large. Therefore, the high-alumina ceramics produced in the prior art are prone to major defects in quality, such as the presence of large open or closed pores and uneven distribution, which will greatly reduce the mechanical strength and electrical properties of the high-alumina ceramics. Summary of the invention

[0004] The purpose of the present invention is to provide a preparation method of high-alumina ceramics and high-alumina ceramics, aiming to improve the quality defects of existing high-alumina ceramics.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for preparing high-alumina ceramics comprises the following steps:

[0007] (1) preparing a ceramic slurry: weighing 6.5-9 kg of small material, 5-7 kg of deionized water, 22-34 ml of a composite amino acid emulsifier and 12-20 ml of an active ingredient, and sequentially adding them into a ball mill for a first grinding; then weighing 93.5-127 kg of α-alumina powder, 30-40.7 kg of deionized water and 2-3.2 kg of a composite emulsifier, and sequentially adding them into a ball mill for a second grinding to obtain a ceramic slurry;

[0008] (2) Spray granulation: The ceramic slurry is sprayed into a granulation tower by a sprayer for atomization. The atomized ceramic slurry is quickly dried to obtain ceramic powder;

[0009] (3) Dry pressing: The ceramic powder is pressed into a shape by a dry press to obtain a green body;

[0010] (4) High-temperature sintering: The embryo is sintered in a push-plate electric kiln, and after natural cooling, a semi-finished high-aluminum ceramic is obtained. The semi-finished high-aluminum ceramic is ground and polished to obtain a finished high-aluminum ceramic.

[0011] Preferably, the small material is composed of a carrier, calcium carbonate powder and Suzhou kaolin, and the ratio of the carrier, the calcium carbonate powder and the Suzhou kaolin is 2:5:3.

[0012] Preferably, the carrier is one or more of aluminum oxide powder, silicon oxide powder, magnesium oxide powder, calcium oxide powder, barium oxide powder and zirconium oxide powder.

[0013] Preferably, the composite amino acid emulsifying aid is prepared by mixing 8-12% of glycerol, 5-8% of carbon ammonia, 65-85% of aqueous ammonia and 2-15% of carboxymethyl cellulose, calculated by mass percentage.

[0014] Preferably, the active ingredient is prepared by mixing 15-35% acrylic acid, 5-15% dilute sulfuric acid and 50-80% xylene in terms of mass percentage;

[0015] Or it can be prepared by mixed reaction of 15-25% acrylic acid, 5-35% dilute phosphoric acid and 50-80% xylene.

[0016] Preferably, the composite emulsifier is prepared by mixing 80-85% of polyvinyl alcohol, 12.5-17% of gum arabic and 1-3% of tributyl phosphate, calculated by mass percentage.

[0017] Preferably, the first grinding time is 3 to 5 hours.

[0018] Preferably, the second grinding time is 12 to 16 hours.

[0019] Also provided is a high-alumina ceramic, which is prepared according to the above-mentioned preparation method of the high-alumina ceramic.

[0020] After adopting the above technical solution, the present invention has the following advantages compared with the background technology:

[0021] The present invention effectively coordinates the ratio of each component in the steps of preparing ceramic slurry, the order of addition, etc., and prepares active ingredients, composite emulsifiers, carriers and composite amino acid emulsifying aids for use as composite defoamers in the preparation of high-alumina ceramic slurry, which effectively eliminates bubbles in the ceramic slurry, homogenizes each component, increases the fluidity of the ceramic slurry, is more conducive to molding, and greatly eliminates larger pores and the number of pores in the high-alumina ceramic structure, thereby effectively improving various performance indicators of the high-alumina ceramic. DETAILED DESCRIPTION

[0022] For ease of understanding of the present invention, the present invention will be described more fully below. Although the present application provides preferred embodiments of the present invention, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive. Where specific techniques or conditions are not indicated in the embodiments, the technical conditions described in the documents in this area or the product specifications are carried out.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0024] In the present invention, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0025] In the present invention, when it comes to numerical ranges, unless otherwise specified, the above numerical ranges are deemed to be continuous and include the minimum and maximum values ​​of the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges included therein.

[0026] Only some numerical ranges are specifically disclosed herein. However, any lower limit can be combined with any upper limit to form an unspecified range; and any lower limit can be combined with other lower limits to form an unspecified range, and likewise any upper limit can be combined with any other upper limit to form an unspecified range. In addition, each separately disclosed point or single value can itself be combined as a lower limit or upper limit with any other point or single value or with other lower limits or upper limits to form an unspecified range.

[0027] The temperature parameters in the present invention, if not specifically limited, allow for both constant temperature treatment and treatment within a certain temperature range. The constant temperature treatment allows the temperature to fluctuate within the precision range controlled by the instrument.

[0028] In the description of the invention, "plurality" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0029] If there is no special description, all embodiments and optional embodiments of the present invention can be combined with each other to form a new technical solution. If there is no special description, all technical features and optional technical features of the present invention can be combined with each other to form a new technical solution.

[0030] If not specifically stated, all steps of the present invention may be performed sequentially or randomly, but are preferably performed sequentially.

[0031] The reagents and instruments used without indicating the manufacturer are all conventional products obtained from the market.

[0032] Embodiment 1

[0033] This embodiment provides a method for preparing high-aluminum ceramics, comprising the following steps:

[0034] (1) Preparation of ceramic slurry: Weigh 6.5 kg of small material, 5 kg of deionized water, 22 ml of composite amino acid emulsifier and 12 ml of active ingredient, and add them into a ball mill in sequence for first grinding, the first grinding time is 3 h; then weigh 93.5 kg of α-alumina powder, 30 kg of deionized water and 2 kg of composite emulsifier, and add them into a ball mill in sequence for second grinding, the second grinding time is 12 h, to obtain ceramic slurry;

[0035] (2) Spray granulation: The ceramic slurry is sprayed into a granulation tower by a sprayer for atomization. The atomized ceramic slurry is quickly dried to obtain ceramic powder;

[0036] (3) Dry pressing: The ceramic powder is pressed into a shape by a dry press to obtain a green body;

[0037] (4) High-temperature sintering: The embryo is sintered in a push-plate electric kiln, and after natural cooling, a semi-finished high-aluminum ceramic is obtained. The semi-finished high-aluminum ceramic is ground and polished to obtain a finished high-aluminum ceramic.

[0038] The small material is composed of 1.3 kg of carrier, 3.25 kg of calcium carbonate powder and 1.95 kg of Suzhou kaolin, and the carrier is silicon oxide powder, preferably silicon dioxide powder;

[0039] The composite amino acid emulsifying aid is prepared by mixing 8% glycerol, 7% carbon ammonia, 75% ammonia water and 10% carboxymethyl cellulose according to mass percentage;

[0040] The active ingredient is obtained by mixing 15% acrylic acid, 12% dilute sulfuric acid and 73% xylene in terms of mass percentage;

[0041] The composite emulsifier is prepared by mixing 80% of polyvinyl alcohol, 17% of gum arabic and 3% of tributyl phosphate in terms of mass percentage.

[0042] Embodiment 2

[0043] This embodiment provides a method for preparing high-aluminum ceramics, comprising the following steps:

[0044] (1) Preparation of ceramic slurry: weigh 7.8 kg of small material, 6 kg of deionized water, 28 ml of composite amino acid emulsifier and 16 ml of active ingredient, and add them into a ball mill in sequence for the first grinding, the first grinding time is 4 hours; then weigh 110.3 kg of α-alumina powder, 35.4 kg of deionized water and 2.6 kg of composite emulsifier, and add them into a ball mill in sequence for the second grinding, the second grinding time is 13 hours, to obtain ceramic slurry;

[0045] (2) Spray granulation: The ceramic slurry is sprayed into a granulation tower by a sprayer for atomization. The atomized ceramic slurry is quickly dried to obtain ceramic powder;

[0046] (3) Dry pressing: The ceramic powder is pressed into a shape by a dry press to obtain a green body;

[0047] (4) High-temperature sintering: The embryo is sintered in a push-plate electric kiln, and after natural cooling, a semi-finished high-aluminum ceramic is obtained. The semi-finished high-aluminum ceramic is ground and polished to obtain a finished high-aluminum ceramic.

[0048] Among them, the small material is composed of 1.56kg of carrier, 3.9kg of calcium carbonate powder and 2.34kg of Suzhou kaolin, and the carrier is magnesium oxide powder;

[0049] The composite amino acid emulsifying aid is prepared by mixing 10% glycerol, 6.5% carbon ammonia, 75% ammonia water and 8.5% carboxymethyl cellulose in terms of mass percentage;

[0050] The active ingredient is prepared by mixing 25% acrylic acid, 10% dilute sulfuric acid and 65% xylene in terms of mass percentage;

[0051] The composite emulsifier is prepared by mixing 83.5% of polyvinyl alcohol, 14.5% of gum arabic and 2% of tributyl phosphate in terms of mass percentage.

[0052] Embodiment 3

[0053] This embodiment provides a method for preparing high-aluminum ceramics, comprising the following steps:

[0054] (1) Preparation of ceramic slurry: weigh 9 kg of small material, 7 kg of deionized water, 34 ml of composite amino acid emulsifier and 20 ml of active ingredient, and add them into a ball mill in sequence for first grinding, the first grinding time is 5 h; then weigh 127 kg of α-alumina powder, 40.7 kg of deionized water and 3.2 kg of composite emulsifier, and add them into a ball mill in sequence for second grinding, the second grinding time is 16 h, to obtain ceramic slurry;

[0055] (2) Spray granulation: The ceramic slurry is sprayed into a granulation tower by a sprayer for atomization. The atomized ceramic slurry is quickly dried to obtain ceramic powder;

[0056] (3) Dry pressing: The ceramic powder is pressed into a shape by a dry press to obtain a green body;

[0057] (4) High-temperature sintering: The embryo is sintered in a push-plate electric kiln, and after natural cooling, a semi-finished high-aluminum ceramic is obtained. The semi-finished high-aluminum ceramic is ground and polished to obtain a finished high-aluminum ceramic.

[0058] Among them, the small material is composed of 1.8kg of carrier, 4.5kg of calcium carbonate powder and 2.7kg of Suzhou kaolin, and the carrier is alumina powder;

[0059] The composite amino acid emulsifying agent is prepared by mixing 12% glycerol, 6% carbon ammonia, 74% ammonia water and 8% carboxymethyl cellulose according to mass percentage;

[0060] The active ingredient is obtained by mixing 35% acrylic acid, 6% dilute sulfuric acid and 59% xylene in terms of mass percentage;

[0061] The composite emulsifier is prepared by mixing 85% of polyvinyl alcohol, 13.5% of gum arabic and 1.5% of tributyl phosphate in terms of mass percentage.

[0062] Embodiment 4

[0063] This embodiment provides a method for preparing high-aluminum ceramics, comprising the following steps:

[0064] (1) Preparation of ceramic slurry: Weigh 6.5 kg of small material, 5 kg of deionized water, 22 ml of composite amino acid emulsifier and 12 ml of active ingredient, and add them into a ball mill in sequence for first grinding, the first grinding time is 3 h; then weigh 93.5 kg of α-alumina powder, 30 kg of deionized water and 2 kg of composite emulsifier, and add them into a ball mill in sequence for second grinding, the second grinding time is 12 h, to obtain ceramic slurry;

[0065] (2) Spray granulation: The ceramic slurry is sprayed into a granulation tower by a sprayer for atomization. The atomized ceramic slurry is quickly dried to obtain ceramic powder;

[0066] (3) Dry pressing: The ceramic powder is pressed into a shape by a dry press to obtain a green body;

[0067] (4) High-temperature sintering: The embryo is sintered in a push-plate electric kiln, and after natural cooling, a semi-finished high-aluminum ceramic is obtained. The semi-finished high-aluminum ceramic is ground and polished to obtain a finished high-aluminum ceramic.

[0068] The small material is composed of 1.3 kg of carrier, 3.25 kg of calcium carbonate powder and 1.95 kg of Suzhou kaolin, and the carrier is silicon oxide powder, preferably silicon dioxide powder;

[0069] The composite amino acid emulsifying aid is prepared by mixing 9% glycerol, 5% carbon ammonia, 71% ammonia water and 15% carboxymethyl cellulose in terms of mass percentage;

[0070] The active ingredient is obtained by mixing 22% acrylic acid, 5% dilute phosphoric acid and 73% xylene in terms of mass percentage;

[0071] The composite emulsifier is prepared by mixing 82% of polyvinyl alcohol, 16.5% of gum arabic and 1.5% of tributyl phosphate in terms of mass percentage.

[0072] Comparative Example 1

[0073] The difference between this comparative example and Example 1 is that the method for preparing ceramic slurry in step (1) is different, and the other steps are the same as Example 1. Among them, the method for preparing ceramic slurry in step (1) of this comparative example is: weigh 5 kg of small material, 3 kg of deionized water, 15 ml of composite amino acid emulsifier, 10 ml of active ingredient, 80 kg of α-alumina powder, 11 kg of deionized water and 1.2 kg of composite emulsifier, and add them into a ball mill in sequence for grinding for 10 hours to obtain ceramic slurry.

[0074] Among them, the small material is composed of 1kg of carrier, 2.5kg of calcium carbonate powder and 1.5kg of Suzhou kaolin, and the carrier is silicon dioxide powder.

[0075] Comparative Example 2

[0076] The difference between this comparative example and Example 1 is that the composition ratio of the composite amino acid emulsifying aid, the active ingredient and the composite emulsifier is different, and the other steps are the same as those of Example 1, wherein in this comparative example:

[0077] The composite amino acid emulsifying aid is prepared by mixing 6% glycerol, 20% carbon ammonia, 61% ammonia water and 13% carboxymethyl cellulose in terms of mass percentage;

[0078] The active ingredient is prepared by mixing 12% acrylic acid, 20% dilute sulfuric acid and 68% xylene in terms of mass percentage;

[0079] The composite emulsifier is prepared by mixing 75% of polyvinyl alcohol, 20% of gum arabic and 5% of tributyl phosphate in terms of mass percentage.

[0080] Test example

[0081] The high-alumina ceramic product prepared by the preparation method of the high-alumina ceramic of the present invention was inspected for appearance and passed the inspection. During the preparation process, 120 standard test bars or discs were pressed by a dry press for average porosity and average bending strength testing. The test results are shown in Table 1.

[0082] Table 1 Porosity and bending strength test results of high alumina ceramics

[0083] Porosity Bending strength Comparative Example 1 2.93％ 335.65MPa Comparative Example 2 3.31％ 332.25MPa Embodiment 1 1.52％ 386.12MPa Embodiment 2 1.72％ 384.36MPa Embodiment 3 1.54％ 380.47MPa Embodiment 4 1.65％ 381.16MPa

[0084] Moreover, 50 experimental data were randomly selected from each test group, and it was found that the discrete range of the bending strength of comparative examples 1 and 2 was between 255 and 412 MPa, while the discrete range of the bending strength of embodiments 1, 2, 3 and 4 of the present invention was between 320 and 428 MPa. It can be seen that the overall strength of the high-aluminum ceramics of the present invention is improved and the comprehensive performance is improved.

[0085] In summary, the porosity of the high-alumina ceramics prepared by the preparation method of high-alumina ceramics according to the present invention is reduced to below 1.8%, the flexural strength is increased to above 380 MPa, and the discrete range is increased to between 320 and 428 MPa, which greatly eliminates the larger pores and the number of pores in the high-alumina ceramic structure, thereby effectively improving the various performance indicators of the high-alumina ceramics.

[0086] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for preparing high-alumina ceramics, characterized in that: The following steps are involved: (1) preparing a ceramic slurry: weighing 6.5-9 kg of small material, 5-7 kg of deionized water, 22-34 ml of a composite amino acid emulsifier and 12-20 ml of an active ingredient, and sequentially adding them into a ball mill for a first grinding; then weighing 93.5-127 kg of α-alumina powder, 30-40.7 kg of deionized water and 2-3.2 kg of a composite emulsifier, and sequentially adding them into a ball mill for a second grinding to obtain a ceramic slurry; (2) Spray granulation: The ceramic slurry is sprayed into a granulation tower by a sprayer for atomization. The atomized ceramic slurry is quickly dried to obtain ceramic powder; (3) Dry pressing: The ceramic powder is pressed into a shape by a dry press to obtain a green body; (4) High-temperature sintering: The embryo is sintered in a push-plate electric kiln, and after natural cooling, a semi-finished high-aluminum ceramic is obtained. The semi-finished high-aluminum ceramic is ground and polished to obtain a finished high-aluminum ceramic.

2. The method for preparing high-alumina ceramics according to claim 1, characterized in that: The small material is composed of a carrier, calcium carbonate powder and Suzhou kaolin, and the ratio of the carrier, the calcium carbonate powder and the Suzhou kaolin is 2:5:

3.

3. The method for preparing high-alumina ceramics according to claim 2, characterized in that: The carrier is one or more of aluminum oxide powder, silicon oxide powder, magnesium oxide powder, calcium oxide powder, barium oxide powder and zirconium oxide powder.

4. The method for preparing high-alumina ceramics according to claim 1, characterized in that: The composite amino acid emulsifying aid is prepared by mixing 8-12% of glycerol, 5-8% of carbon ammonia, 65-85% of ammonia water and 2-15% of carboxymethyl cellulose in terms of mass percentage.

5. The method for preparing high-alumina ceramics according to claim 1, characterized in that: The active ingredient is prepared by mixing 15-35% acrylic acid, 5-15% dilute sulfuric acid and 50-80% xylene in terms of mass percentage; Or it can be prepared by mixed reaction of 15-35% acrylic acid, 5-15% dilute phosphoric acid and 50-80% xylene.

6. The method for preparing high-alumina ceramics according to claim 1, characterized in that: The composite emulsifier is prepared by mixing 80-85% of polyvinyl alcohol, 12.5-17% of gum arabic and 1-3% of tributyl phosphate in terms of mass percentage.

7. The method for preparing high-alumina ceramics according to claim 1, characterized in that: The first grinding time is 3 to 5 hours.

8. The method for preparing high-alumina ceramics according to claim 1, characterized in that: The second grinding time is 12 to 16 hours.

9. A high-alumina ceramic, characterized in that: The high-alumina ceramic is prepared according to the preparation method of any one of claims 1 to 8.