A production process for precision ceramic material

Abstract

The invention relates to the technical field of alumina ceramics, and discloses a production process of precision ceramic materials. The invention ball-mills a sulfonated polyvinyl alcohol dispersant and alumina, then pours the slurry into a mold, dries, presses into a green body, and sinters to obtain a precision ceramic material. The sulfonated polyvinyl alcohol dispersant of the invention is used as a dispersant and a binder to perform ball-milling modification on alumina, and sinter to obtain a precision ceramic material. The side chain of the sulfonated polyvinyl alcohol dispersant contains a large number of sodium sulfonate groups, which have a strong interaction with the surface of alumina, so that the polyvinyl alcohol dispersant is coated on the surface of alumina, inhibiting the agglomeration of alumina and improving the dispersibility. At the same time, polyvinyl alcohol can be used as a polymer-based binder to make the alumina particles more tightly and firmly bonded, significantly improving the relative density, compactness and flexural strength of alumina ceramics.

Description

Technical Field

[0001] The invention relates to the technical field of alumina ceramics, in particular to a production process of a precision ceramic material. Background Art

[0002] Alumina ceramics have high wear resistance, good corrosion resistance, and high temperature resistance, and are widely used in advanced ceramic materials, building materials, aerospace and other fields. In order to improve the dispersibility of alumina in ceramics, reduce agglomeration, and improve the mechanical strength of ceramics, it is usually necessary to add dispersants, binders and other additives. Common dispersants include sodium polyacrylate, sodium dodecyl sulfonate, polydiallyl dimethyl ammonium chloride, etc.; binders mainly include phenolic resin, polyvinyl alcohol, sodium carboxymethyl cellulose, etc.

[0003] Polyvinyl alcohol is a non-toxic, environmentally friendly, biodegradable, cheap and readily available polymer material, which is widely used in bonding agents, ceramics, plastics, etc. The invention patent with announcement number CN102153335B discloses a machinable alumina ceramic and its preparation method, using polyvinyl alcohol 1799 as a binder, nano-alumina and flaky alumina as a ceramic matrix, and the obtained alumina ceramic has high bending strength and fracture toughness. However, the alumina ceramic needs to add additives such as magnesium oxide and titanium dioxide, and the raw materials are relatively complex. The present invention aims to use sulfonated polyvinyl alcohol as a dispersant and a binder to improve the mechanical strength and other properties of alumina ceramic materials. Summary of the invention

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

[0005] The technical solution provided by the present invention is: a production process of precision ceramic materials:

[0006] (1) Add 1,4-dioxane, water, and polyvinyl alcohol to a reaction vessel, heat to 95-100°C, stir to dissolve, and then cool to the reaction temperature. Add sodium hydroxide and 1,4-butane sultone. Stir to react, then distill the solution under reduced pressure to remove 1,4-dioxane, cool in an ice-water bath, add saturated sodium chloride solution to precipitate, filter, wash with ethanol, and dry to obtain a sulfonated polyvinyl alcohol dispersant. The reaction formula is:

[0007]

[0008] (2) Add water, sulfonated polyvinyl alcohol dispersant, and alumina into a planetary ball mill for ball milling. Then pour the slurry into a mold and place it in an oven for drying. Then press the material into a green body, and finally sinter it in a vacuum sintering furnace and cool it to obtain a precision ceramic material.

[0009] Preferably, in (1), the volume ratio of 1,4-dioxane to water is 1:(0.4-0.6).

[0010] Preferably, in (1), the mass of sodium hydroxide and 1,4-butanesultone is (6-18)% and (20-60)% of the mass of polyvinyl alcohol, respectively.

[0011] Preferably, in (1), the reaction temperature is 60-75°C and the reaction time is 18-24h.

[0012] Preferably, in (2), the mass of the sulfonated polyvinyl alcohol dispersant is (0.5-3)% of the mass of the alumina.

[0013] Preferably, in (2), the ratio of alumina to water is (350-450) g:1L.

[0014] Preferably, in (2), the rotation speed during ball milling is 300-500 r / min, and the time is 3-8 h.

[0015] Preferably, in (2), the sintering pressure is 10-15 MPa, the temperature is 1350-1500° C., and the sintering time is 2-3 h.

[0016] The technical effect of the present invention is as follows: the present invention utilizes the hydroxyl group of polyvinyl alcohol to react with 1,4-butane sultone to obtain a sulfonated polyvinyl alcohol dispersant, which is used as a dispersant and a binder to perform ball milling modification on alumina, and sinter to obtain a precision ceramic material. The side chain of the sulfonated polyvinyl alcohol dispersant contains a large number of sodium sulfonate groups, which have a strong interaction with the surface of alumina, so that the polyvinyl alcohol dispersant is coated on the surface of alumina, inhibiting the agglomeration of alumina and improving the dispersibility. At the same time, polyvinyl alcohol can be used as a polymer-based binder to make the alumina particles more tightly and firmly bonded, significantly improving the relative density, compactness and flexural strength of alumina ceramics. DETAILED DESCRIPTION

[0017] In order to understand the technical features and contents of the present invention in detail, the preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described in the embodiments, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described here.

[0018] The average particle size of the aluminum oxide of the present invention is 5 μm.

[0019] Example 1

[0020] (1) Add 100 mL of 1,4-dioxane, 50 mL of water, and 4 g of polyvinyl alcohol (polyvinyl alcohol 1799) to a reaction vessel, heat to 95°C, stir to dissolve, and then cool to 65°C. Add 0.42 g of sodium hydroxide and 1.3 g of 1,4-butanesulfonate, stir to react for 18 hours, remove 1,4-dioxane by vacuum distillation, cool in an ice water bath, add saturated sodium chloride solution to precipitate, filter, wash with ethanol, and dry to obtain a sulfonated polyvinyl alcohol dispersant.

[0021] (2) Add 1L of water, 2g of sulfonated polyvinyl alcohol dispersant, and 400g of alumina to a planetary ball mill, set the speed to 400r / min, and ball mill for 6h. Then pour the slurry into a mold, place it in an oven, and dry it at 100℃ for 12h. Then press the material into a green body. Finally, sinter it in a vacuum sintering furnace at 10MPa and 1500℃ for 2h. Cool it to obtain a precision ceramic material.

[0022] Example 2

[0023] (1) Add 100 mL of 1,4-dioxane, 40 mL of water, and 4 g of polyvinyl alcohol (polyvinyl alcohol 1799) to a reaction vessel, heat to 100°C, stir to dissolve, and then cool to 60°C. Add 0.24 g of sodium hydroxide and 0.8 g of 1,4-butanesulfonate, stir to react for 18 hours, remove 1,4-dioxane by vacuum distillation, cool in an ice water bath, add saturated sodium chloride solution to precipitate, filter, wash with ethanol, and dry to obtain a sulfonated polyvinyl alcohol dispersant.

[0024] (2) Add 1L of water, 3.5g of sulfonated polyvinyl alcohol dispersant, and 350g of alumina to a planetary ball mill, set the speed to 300r / min, and ball mill for 8h. Then pour the slurry into a mold, place it in an oven, and dry it at 100℃ for 12h. Then press the material into a green body. Finally, sinter it in a vacuum sintering furnace at 15MPa and 1400℃ for 2h, cool it, and obtain a precision ceramic material.

[0025] Example 3

[0026] (1) Add 100 mL of 1,4-dioxane, 60 mL of water, and 4 g of polyvinyl alcohol (polyvinyl alcohol 1799) to a reaction vessel, heat to 95°C, stir to dissolve, and then cool to 60°C. Add 0.72 g of sodium hydroxide and 2.4 g of 1,4-butanesulfonate, stir to react for 24 hours, remove 1,4-dioxane by vacuum distillation, cool in an ice water bath, add saturated sodium chloride solution to precipitate, filter, wash with ethanol, and dry to obtain a sulfonated polyvinyl alcohol dispersant.

[0027] (2) Add 1L of water, 9g of sulfonated polyvinyl alcohol dispersant, and 450g of alumina to a planetary ball mill, set the speed to 500r / min, and ball mill for 3h. Then pour the slurry into a mold, place it in an oven, and dry it at 100℃ for 12h. Then press the material into a green body. Finally, sinter it in a vacuum sintering furnace at 15MPa and 1350℃ for 3h. Cool it to obtain a precision ceramic material.

[0028] Example 4

[0029] (1) Add 100 mL of 1,4-dioxane, 50 mL of water, and 4 g of polyvinyl alcohol (polyvinyl alcohol 1799) to a reaction vessel, heat to 100°C, stir to dissolve, and then cool to 75°C. Add 0.57 g of sodium hydroxide and 1.9 g of 1,4-butanesulfonate, stir to react for 18 hours, remove 1,4-dioxane by vacuum distillation, cool in an ice water bath, add saturated sodium chloride solution to precipitate, filter, wash with ethanol, and dry to obtain a sulfonated polyvinyl alcohol dispersant.

[0030] (2) Add 1L of water, 12g of sulfonated polyvinyl alcohol dispersant, and 400g of alumina to a planetary ball mill, set the speed to 400r / min, and ball mill for 8h. Then pour the slurry into a mold, place it in an oven, and dry it at 100℃ for 12h. Then press the material into a green body. Finally, sinter it in a vacuum sintering furnace at 10MPa and 1500℃ for 2h. Cool it to obtain a precision ceramic material.

[0031] Comparative Example 1

[0032] (1) Add 1L of water and 400g of alumina to a planetary ball mill, set the speed to 400r / min, and perform ball milling for 6h. Then pour the slurry into a mold, place it in an oven, and dry it at 100℃ for 12h. Then press the material into a green body. Finally, sinter it in a vacuum sintering furnace at 10MPa and 1500℃ for 2h. Cool it to obtain a precision ceramic material.

[0033] Comparative Example 2

[0034] (1) Add 1L of water, 2g of polyvinyl alcohol (polyvinyl alcohol 1799), and 400g of alumina to a planetary ball mill, set the speed to 400r / min, and ball mill for 6h. Then pour the slurry into a mold, place it in an oven, and dry it at 100℃ for 12h. Then press the material into a green body. Finally, sinter it in a vacuum sintering furnace at 10MPa and 1500℃ for 2h, cool it, and obtain a precision ceramic material.

[0035] Comparative Example 3

[0036] (1) Add 1L of water, 2g of sodium dodecyl sulfate, and 400g of alumina to a planetary ball mill, set the speed to 400r / min, and ball mill for 6h. Then pour the slurry into a mold, place it in an oven, and dry it at 100℃ for 12h. Then press the material into a green body. Finally, sinter it in a vacuum sintering furnace at 10MPa and 1500℃ for 2h, cool it, and obtain a precision ceramic material.

[0037] 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.

[0038] 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.

[0039] Table 1 Precision ceramic material performance test

[0040]

[0041] It can be seen from Table 1 that compared with Comparative Example 1, sulfonated polyvinyl alcohol dispersants are added to Examples 1-4. The side chains of the dispersants contain a large number of sodium sulfonate groups, which have a strong interaction with the surface of alumina, so that the polyvinyl alcohol dispersant is coated on the surface of alumina, inhibiting the agglomeration of alumina and improving the dispersibility. At the same time, polyvinyl alcohol can be used as a polymer-based binder to make the alumina particles more tightly and firmly bonded, which is beneficial to improve the relative density, compactness and flexural strength of alumina ceramics.

[0042] In Comparative Example 2, polyvinyl alcohol is used as a dispersant and a binder. Polyvinyl alcohol does not contain a sodium sulfonate group, has a weak interaction with the surface of alumina, cannot be coated on the surface of alumina particles, and has poor ability to improve agglomeration and increase dispersibility, resulting in a relative density and flexural strength of the alumina ceramic being lower than those in the embodiments.

[0043] In Comparative Example 3, sodium dodecyl sulfate is used as a dispersant, which has a certain degree of dispersibility for the alumina particles. However, sodium dodecyl sulfate cannot act as a binder, resulting in a relative density and flexural strength of the alumina ceramic being lower than those of the embodiments.

[0044] The above describes some embodiments of the present invention, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A production process for precision ceramic materials, characterized in that: The production process is: (1) Add 1,4-dioxane, water and polyvinyl alcohol to a reaction vessel, heat to 95-100°C, stir to dissolve and then cool to the reaction temperature, add sodium hydroxide and 1,4-butane sultone, stir to react, distill the solution under reduced pressure to remove 1,4-dioxane, cool in an ice water bath, add saturated sodium chloride solution to precipitate, filter, wash with ethanol and dry to obtain a sulfonated polyvinyl alcohol dispersant; (2) Add water, sulfonated polyvinyl alcohol dispersant, and alumina into a planetary ball mill for ball milling, then pour the slurry into a mold, place it in an oven for drying, then press the material into a green body, and finally sinter it in a vacuum sintering furnace and cool it to obtain a precision ceramic material; In the above (1), the mass of sodium hydroxide and 1,4-butanesultone is respectively (6-18)% and (20-60)% of the mass of polyvinyl alcohol; In the above (2), the mass of the sulfonated polyvinyl alcohol dispersant is (0.5-3)% of the mass of the alumina.

2. The production process of precision ceramic materials according to claim 1, characterized in that: In the above (1), the volume ratio of 1,4-dioxane to water is 1:(0.4-0.6).

3. The production process of precision ceramic materials according to claim 1, characterized in that: In the above (1), the reaction temperature is 60-75°C and the reaction time is 18-24h.

4. The production process of precision ceramic materials according to claim 1, characterized in that: In the above (2), the ratio of alumina to water is (350-450) g:1L.

5. The production process of precision ceramic material 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 3-8 h.

6. The production process of precision ceramic material according to claim 1, characterized in that: In the above (2), the pressure during sintering is 10-15 MPa, the temperature is 1350-1500° C., and the time is 2-3 h.

Images