A precision ceramic body and preparation method thereof

Abstract

The invention relates to the technical field of alumina ceramics, and discloses a precision ceramic blank and a preparation method thereof. The invention adds water, betaine-based phenolic resin, and alumina into a planetary ball mill, performs ball milling, then pours the slurry into a mold, places it in an oven for drying, and then presses the material into a blank to obtain a precision ceramic blank. The betaine zwitterionic group of the invention contains quaternary ammonium salt and sulfonate group, and has a strong interaction with the surface of alumina, so that the betaine-based phenolic resin is uniformly modified on the surface of alumina, forms a steric hindrance, inhibits the agglomeration of alumina, improves the dispersibility, and plays a good dispersing role. At the same time, the phenolic resin is used as a binder to form a close bonding effect between alumina particles. After high-temperature sintering, the relative density of the alumina ceramic is significantly improved, and it has high density and bending strength.

Description

Technical Field

[0001] The invention relates to the technical field of alumina ceramics, in particular to a precision ceramic body and a preparation method thereof. Background Art

[0002] Alumina ceramics are usually made of alumina, dispersants, binders and other raw materials through mixing and dispersing, pressing into blanks, high-temperature sintering and other processes. The types of dispersants, binders and other additives have a great influence on the performance of alumina ceramics. Common dispersants and binders for alumina ceramics are sodium polyacrylate, polyacrylamide, phenolic resin, polyvinyl alcohol, etc.

[0003] Phenolic resin is a resin material with high bonding performance, which can be used as a binder and is widely used in ceramics, concrete, cement and other products. The invention patent with announcement number CN117229077 discloses a high-strength refractory material based on ceramic micropowder and its preparation method. Waste sanitary porcelain is used as raw material, nano-alumina and submicron aluminum nitride are introduced as coating materials, and the composite ceramic micropowder is treated with citric acid and phenolic resin to form a phenolic resin coating layer in situ, and then silicon micropowder, corundum powder, mullite powder, and alumina powder are mixed as additives, and the lanthanum zirconium bimetallic organic framework is used to modify the silica sol. The obtained ceramic micropowder refractory material has the advantages of good crack resistance and strong fire resistance. However, the raw materials of this patent are complicated, the preparation process is complex, and it is not suitable for industrial actual production and application. Summary of the invention

[0004] The invention solves the problem of low relative density and mechanical strength of alumina ceramics.

[0005] The technical solution provided by the present invention is a production process of a precision ceramic material and a method for preparing a precision ceramic body, comprising the following steps:

[0006] (1) Add N,N-dimethylformamide, chloromethylphenolic resin, and N,N,N',N'-tetramethylethylenediamine to a reaction flask, stir for a primary reaction, then add sodium 3-chloro-2-hydroxypropanesulfonate for a secondary reaction, cool the solution, pour it into a saturated sodium chloride solution, filter it, wash it with ethanol, and dry it to obtain a betaine-based phenolic resin. The reaction formula is:

[0007]

[0008] (2) Add water, betaine-based phenolic resin, and alumina into a planetary ball mill for ball milling. Then pour the slurry into a mold, place it in an oven for drying, and then press the material into a green body to obtain a precision ceramic green body.

[0009] Preferably, in (1), the mass of N,N,N',N'-tetramethylethylenediamine and sodium 3-chloro-2-hydroxypropanesulfonate is (40-70)%, (75-120)% of the mass of the chloromethylphenol-formaldehyde resin.

[0010] Preferably, in (1), the temperature of the first reaction is 100-120°C, and the time is 24-36 hours; the temperature of the second reaction is 110-130°C, and the time is 36-48 hours.

[0011] Preferably, in (2), the mass of the betaine-based phenolic resin is 1-8% of the mass of the alumina.

[0012] Preferably, in (2), the ratio of alumina to water is (350-500) g:1L.

[0013] Preferably, in (2), the rotation speed during ball milling is 300-500 r / min and the time is 4-10 h.

[0014] Preferably, the preparation method of chloromethyl phenolic resin is as follows: acetone, phenolic resin, 220-360% of zinc chloride by mass of the phenolic resin, and 30-48% of 1,4-dichloromethoxybutane are added into a reaction bottle, the temperature is raised to 55-65° C., the reaction is stirred for 3-5 hours, the solution is poured into water after cooling, filtered, washed with ethanol, and dried to obtain chloromethyl phenolic resin.

[0015] Technical effect: The present invention utilizes chloromethyl phenolic resin to sequentially react with N,N,N',N'-tetramethylethylenediamine and sodium 3-chloro-2-hydroxypropanesulfonate to undergo quaternization reaction to obtain betaine-based phenolic resin, and introduces hydrophilic betaine zwitterionic groups into the side chains of the phenolic resin, thereby significantly improving the water solubility of the phenolic resin, so that the betaine-based phenolic resin can form a homogeneous aqueous slurry system with water and alumina, which is convenient for the subsequent uniform ball milling process.

[0016] The present invention also provides a precision ceramic body prepared according to the above preparation method.

[0017] The betaine zwitterionic group of the invention contains quaternary ammonium salt and sulfonate group, and has strong interaction with the surface of aluminum oxide, so that the betaine-based phenolic resin is evenly modified on the surface of aluminum oxide, forming a steric hindrance, inhibiting the agglomeration of aluminum oxide, improving the dispersibility, and playing a good dispersing role. At the same time, the phenolic resin is used as a binder to form a close bonding effect between aluminum oxide particles. After high-temperature sintering, the relative density of the aluminum oxide ceramic is significantly improved, and the aluminum oxide ceramic has high compactness and bending strength. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to the conventional conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0019] Example 1

[0020] (1) Add 35 mL of acetone, 2 g of phenolic resin, 4.4 g of zinc chloride, and 0.6 g of 1,4-dichloromethoxybutane to a reaction flask, heat to 60°C, stir and react for 3 h, cool and pour the solution into water, filter, wash with ethanol, and dry to obtain chloromethyl phenolic resin.

[0021] (2) Add 140 mL of N,N-dimethylformamide, 4 g of chloromethylphenolic resin, and 2.4 g of N,N,N',N'-tetramethylethylenediamine to a reaction bottle, heat to 100°C, and stir to react for 24 hours. Then add 3.6 g of sodium 3-chloro-2-hydroxypropanesulfonate, heat to 110°C, and stir to react for 48 hours. After cooling, pour the solution into a saturated sodium chloride solution, filter, wash with ethanol, and dry to obtain a betaine-based phenolic resin.

[0022] (3) Add 1L of water, 3.5g of betaine-based phenolic resin, and 350g of alumina with an average particle size of 5μm into a planetary ball mill, control the speed to 400r / min and ball mill for 8h, then pour the slurry into a mold, place it in an oven to dry, and then press the material into a green body to obtain a precision ceramic green body.

[0023] Example 2

[0024] (1) Add 50 mL of acetone, 2 g of phenolic resin, 7.2 g of zinc chloride, and 0.96 g of 1,4-dichloromethoxybutane to a reaction flask, heat to 55 °C, stir and react for 5 h, cool and pour the solution into water, filter, wash with ethanol, and dry to obtain chloromethyl phenolic resin.

[0025] (2) Add 140 mL of N,N-dimethylformamide, 4 g of chloromethylphenolic resin, and 2 g of N,N,N',N'-tetramethylethylenediamine to a reaction bottle, heat to 120°C, and stir to react for 24 hours. Then add 3.6 g of sodium 3-chloro-2-hydroxypropanesulfonate, heat to 130°C, and stir to react for 36 hours. After cooling, pour the solution into a saturated sodium chloride solution, filter, wash with ethanol, and dry to obtain a betaine-based phenolic resin.

[0026] (3) Add 1L of water, 15g of betaine-based phenolic resin, and 500g of alumina with an average particle size of 5μm into a planetary ball mill, control the speed to 400r / min and ball mill for 4h, then pour the slurry into a mold, place it in an oven to dry, and then press the material into a green body to obtain a precision ceramic green body.

[0027] Example 3

[0028] (1) Add 40 mL of acetone, 2 g of phenolic resin, 5.3 g of zinc chloride, and 0.74 g of 1,4-dichloromethoxybutane to a reaction flask, heat to 55 °C, stir and react for 5 h, cool and pour the solution into water, filter, wash with ethanol, and dry to obtain chloromethyl phenolic resin.

[0029] (2) Add 150 mL of N,N-dimethylformamide, 4 g of chloromethylphenolic resin, and 2.8 g of N,N,N',N'-tetramethylethylenediamine to a reaction bottle, heat to 100°C, and stir to react for 36 hours. Then add 4.8 g of sodium 3-chloro-2-hydroxypropanesulfonate, heat to 120°C, and stir to react for 48 hours. After cooling, pour the solution into a saturated sodium chloride solution, filter, wash with ethanol, and dry to obtain a betaine-based phenolic resin.

[0030] (3) Add 1L of water, 2.4g of betaine-based phenolic resin, and 400g of alumina with an average particle size of 5μm into a planetary ball mill, control the speed to 500r / min and ball mill for 10h, then pour the slurry into a mold, place it in an oven to dry, and then press the material into a green body to obtain a precision ceramic green body.

[0031] Example 4

[0032] (1) Add 50 mL of acetone, 2 g of phenolic resin, 6.3 g of zinc chloride, and 0.85 g of 1,4-dichloromethoxybutane to a reaction flask, heat to 65 °C, stir and react for 3 h, cool and pour the solution into water, filter, wash with ethanol, and dry to obtain chloromethyl phenolic resin.

[0033] (2) Add 120 mL of N,N-dimethylformamide, 4 g of chloromethylphenolic resin, and 1.6 g of N,N,N',N'-tetramethylethylenediamine to a reaction bottle, heat to 100°C, and stir to react for 36 hours. Then add 3 g of sodium 3-chloro-2-hydroxypropanesulfonate, heat to 130°C, and stir to react for 36 hours. After cooling, pour the solution into a saturated sodium chloride solution, filter, wash with ethanol, and dry to obtain a betaine-based phenolic resin.

[0034] (3) Add 1L of water, 3.2g of betaine-based phenolic resin, and 400g of alumina with an average particle size of 5μm into a planetary ball mill, control the speed to 300r / min and ball mill for 10h, then pour the slurry into a mold, place it in an oven to dry, and then press the material into a green body to obtain a precision ceramic green body.

[0035] Comparative Example 1

[0036] (1) Add 1L of water and 350g of alumina with an average particle size of 5μm into a planetary ball mill, control the speed to 400r / min and ball mill for 8h, then pour the slurry into a mold, place it in an oven to dry, and then press the material into a green body to obtain a precision ceramic green body.

[0037] Comparative Example 2

[0038] (1) Add 1L of water, 3.5g of phenolic resin, and 350g of alumina with an average particle size of 5μm into a planetary ball mill, control the speed to 400r / min and ball mill for 8h, then pour the slurry into a mold, place it in an oven to dry, and then press the material into a green body to obtain a precision ceramic green body.

[0039] Comparative Example 3

[0040] (1) Add 1L of water, 3.5g of chloromethylphenol-formaldehyde resin (prepared in Example 1), and 350g of alumina with an average particle size of 5μm into a planetary ball mill, control the speed to 400r / min and ball mill for 8h, then pour the slurry into a mold, place it in an oven to dry, and then press the material into a green body to obtain a precision ceramic green body.

[0041] Comparative Example 4

[0042] (1) Add 140 mL of N,N-dimethylformamide, 4 g of chloromethylphenolic resin, and 2.4 g of N,N,N',N'-tetramethylethylenediamine to a reaction bottle, heat to 100°C, stir and react for 24 hours, cool the solution, pour it into a saturated sodium chloride solution, filter it, wash it with ethanol, and dry it to obtain a cationic phenolic resin.

[0043] (2) Add 1L of water, 3.5g of cationic phenolic resin, and 350g of alumina with an average particle size of 5μm into a planetary ball mill, control the speed to 400r / min and ball mill for 8h, then pour the slurry into a mold, place it in an oven to dry, and then press the material into a green body to obtain a precision ceramic green body.

[0044] The precision ceramic bodies prepared in the examples and comparative examples were placed in a vacuum sintering furnace, sintered at 1400° C. for 3 h at 15 MPa, and cooled to obtain precision ceramic materials.

[0045] The relative density of alumina ceramic samples was tested according to the Archimedes method. Each sample was tested 5 times and the average value was taken.

[0046] The three-point bending method was used to test the bending strength of alumina ceramic samples, the sample size was 35 mm × 4 mm × 3 mm, and the loading rate was 0.5 mm / min. The test results are shown in Table 1.

[0047] Table 1 Precision ceramic material performance test

[0048]

[0049] After testing, compared with Comparative Example 1, in Examples 1-4, betaine-based phenolic resin was added when preparing the precision ceramic body. The hydrophilic betaine zwitterionic groups contained in the side chains of the phenolic resin significantly improved the water solubility of the phenolic resin, and can form a homogeneous aqueous slurry system with water and alumina, which is convenient for the subsequent uniform ball milling process. In addition, the betaine zwitterionic groups contain quaternary ammonium salts and sulfonate groups, which have a strong interaction with the surface of alumina, so that the betaine-based phenolic resin is uniformly modified on the surface of alumina, forming a steric hindrance effect, inhibiting the agglomeration of alumina, improving the dispersibility, and playing a good dispersing effect. At the same time, the phenolic resin acts as a binder to form a tight bonding effect between the alumina particles. After high-temperature sintering, the relative density of the alumina ceramic is significantly improved, and it has high density and flexural strength.

[0050] The phenolic resin added in Comparative Examples 2 and 3, the chloromethyl phenolic resin does not contain the hydrophilic betaine zwitterionic group, has very poor water solubility, cannot form a homogeneous dispersion system with water and alumina during the ball milling process, and the ball milling effect is poor. In addition, the phenolic resins of the two do not contain quaternary ammonium salt and sulfonate groups, have low interaction with the surface of alumina, cannot play the role of a dispersant, do not inhibit the agglomeration of alumina, and the relative density and flexural strength of the alumina ceramics after high-temperature sintering are low.

[0051] In Comparative Example 4, when preparing the cationic phenolic resin, no sodium 3-chloro-2-hydroxypropanesulfonate was added. The obtained phenolic resin did not contain sulfonate groups, had poor interaction with the surface of alumina, had poor dispersion, and was difficult to effectively inhibit the agglomeration of alumina. After high-temperature sintering, the relative density and flexural strength of the alumina ceramic were lower than those in the embodiments.

Claims

1. A method for preparing a precision ceramic body, characterized in that: The preparation method is: (1) Add N,N-dimethylformamide, chloromethylphenolic resin, and N,N,N',N'-tetramethylethylenediamine to a reaction flask, stir to carry out a primary reaction, then add sodium 3-chloro-2-hydroxypropanesulfonate to carry out a secondary reaction, and after cooling, pour the solution into a saturated sodium chloride solution, filter, wash with ethanol, and dry to obtain a betaine-based phenolic resin; (2) Add water, betaine-based phenolic resin, and alumina into a planetary ball mill for ball milling, then pour the slurry into a mold, place it in an oven for drying, and then press the material into a green body to obtain a precision ceramic green body; In the above (1), the mass of N,N,N',N'-tetramethylethylenediamine and sodium 3-chloro-2-hydroxypropanesulfonate is (40-70)%, (75-120)% of the mass of chloromethylphenol-formaldehyde resin; In (1), the temperature of the first reaction is 100-120°C and the time is 24-36h; the temperature of the second reaction is 110-130°C and the time is 36-48h; The preparation reaction formula of the betaine-based phenolic resin is: 。 2. The preparation method according to claim 1, characterized in that: In the above (2), the mass of the betaine-based phenolic resin is 1-8% of the mass of the alumina.

3. The preparation method according to claim 1, characterized in that: In the above (2), the ratio of aluminum oxide to water is (350-500) g:1L.

4. The preparation method according to claim 1, characterized in that: In the above (2), the rotation speed during ball milling is 300-500 r / min and the time is 4-10 h.

5. The preparation method according to claim 1, characterized in that: The preparation method of the chloromethyl phenolic resin comprises the following steps: adding acetone, phenolic resin, zinc chloride and 1,4-dichloromethoxybutane into a reaction bottle, cooling after reaction, pouring the solution into water, filtering, washing with ethanol and drying to obtain the chloromethyl phenolic resin.

6. The preparation method according to claim 5, characterized in that: The mass of the zinc chloride and 1,4-dichloromethoxybutane is (220-360)%, (30-48)% of the mass of the phenolic resin.

7. The preparation method according to claim 5, characterized in that: The reaction temperature is 55-65°C and the reaction time is 3-5h.

8. A precision ceramic body prepared according to the preparation method according to any one of claims 1 to 7.

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