High-performance yttrium oxide ceramic ring slip casting method

Abstract

The invention discloses a slip casting method for a high-performance yttrium oxide ceramic ring, which comprises the following steps: firstly, carrying out hydrolysis-resistant modification treatment on yttrium oxide powder, then preparing yttrium oxide slurry, preparing a yttrium oxide ceramic green body by adopting pressure slip casting, and sintering to obtain yttrium oxide ceramic. The modified yttrium oxide powder is prepared from the high-performance waterproof coating, hydrolysis of the yttrium oxide powder is effectively prevented through modification, pressure slip casting is adopted, the initial density of the yttrium oxide green body is increased, sintering deformation is effectively prevented, and the method is high in production efficiency, good in green body quality, lower in cost and suitable for industrial production. The prepared yttrium oxide ceramic is good in wear resistance, good in toughness and high in strength.

Description

Technical Field

[0001] The invention relates to the technical field of inorganic ceramic material preparation, and in particular to a slurry injection molding method for a high-performance yttria ceramic ring. Background Art

[0002] Y2O3 ceramics are widely used as laser host materials, high temperature chemical resistant substrates and components of semiconductor devices due to their excellent properties such as high melting point (2430℃), high corrosion resistance and thermal stability. However, with the research progress of Y2O3 ceramics in various practical application fields in recent years, the preparation of this ceramic with complex shape, large size and high reliability has become an increasingly important issue.

[0003] Research shows that compared with dry molding, wet molding can more easily control the agglomeration of the green body and the content of impurities, reduce the defects of the green body, and can produce ceramic parts with various complex shapes. The traditional slip casting process has low cost, simple process, easy operation and control, but the molding shape is rough, the slip casting time is long, and the green body density and strength are not high.

[0004] Unlike ordinary grouting molding, the pressure grouting process uses external pressure to replace capillary force, that is, an airtight plunger is used to press the slurry into the mold. This makes the grouting thickness easier to control, the structure and density of the molded product are uniform, the gel injection molding cycle is short, the performance is reliable, and it is conducive to industrial application production. Summary of the invention

[0005] The purpose of the present invention is to provide a high-performance yttrium oxide ceramic ring slurry molding method. The present invention adopts a pressure slurry molding method to prepare a high-performance yttrium oxide ceramic. This molding method realizes the multifunctional production of high-performance yttrium oxide ceramic products of various complex shapes. We successfully obtained yttrium oxide powder that effectively prevents hydrolysis through the yttrium oxide powder pretreatment process, and solved the hydrolysis problem in the yttrium oxide powder colloidal molding process. The pressure slurry molding is used to increase the initial density of the yttrium oxide blank and effectively prevent sintering deformation. The prepared ceramics can have the advantages of high strength, good toughness, good wear resistance, etc.

[0006] The technical solution adopted by the present invention is as follows: A high-performance yttrium oxide ceramic ring grouting molding method comprises the following steps:

[0007] Step 1: First, yttrium oxide is dispersed in anhydrous ethanol, and the synthetic polymer coating is added under stirring conditions, and then placed in a ball mill for ball milling, and modified yttrium oxide powder is obtained after drying and sieving;

[0008] Step 2: adding deionized water, dispersant, modified yttrium oxide powder, and pH adjuster tetramethylammonium hydroxide into a ball mill, mixing and dispersing, and obtaining a high solid content modified yttrium oxide slurry;

[0009] Step 3: After vacuum degassing, the modified yttrium oxide slurry is injected into a gypsum mold under vibration conditions and pressure to absorb water and dry, and then demolded and dried to obtain an yttrium oxide ceramic body;

[0010] Step 4: Finally, the ceramic body is sintered in a sintering furnace and annealed to obtain yttrium oxide ceramics.

[0011] Preferably, in step one, the mass of yttrium oxide accounts for 30wt%-50wt% of anhydrous ethanol, the synthetic polymer coating is one or more of acrylic ester waterproof coating, silicone waterproof coating, epoxy resin waterproof coating, and the added amount is 5%-15% of the mass of yttrium oxide; the ball-to-material ratio is (1-3): 1; the ball milling time is 16-24h; dried at 50-80°C and passed through a 80-120 mesh sieve.

[0012] Preferably, the dispersant in step 2 is one of ammonium citrate, sodium polyacrylate, and polyethylene glycol, and the amount of the dispersant added is 0.5%-1.2% of the modified yttrium oxide powder; the amount of the pH regulator tetramethylammonium hydroxide added is 0.8-2% of the modified yttrium oxide powder; and the deionized water accounts for 16-20% of the total mass of the slurry;

[0013] Preferably, in step three, the pressure of vacuum degassing is -0.8 to -1 MPa, and the vacuum degassing time is 20-40 min; the pressure of pressure grouting is 0.5-2 MPa; the vibration frequency is 5-25 Hz, and the vibration time is 4-8 h; the specific process of drying after demoulding is: drying in a constant temperature and humidity chamber with a humidity of 30-50% and a temperature of 35-50°C for 15-20 h, and then drying at a temperature of 75-100°C for 15-20 h.

[0014] Preferably, in step 4, the specific sintering process is: in a muffle furnace, the temperature is raised to 800°C at a rate of 1-5°C / min, and kept warm for 1-2 hours. In a vacuum furnace, the temperature is raised to 1250-1350°C at a rate of 1-3°C / min, and the temperature is raised to 1800-1850°C at a rate of 1-2°C / min, and kept warm for 2-5 hours. Finally, the obtained ceramic is annealed in air at 1000-1100°C for 2-3 hours to obtain yttrium oxide ceramics.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] (1) The present invention adopts high-performance polymer coating to prepare modified yttrium oxide powder, and the modification effectively prevents the hydrolysis of yttrium oxide powder.

[0017] (2) The present invention adopts pressure injection molding to increase the initial density of the yttrium oxide green body and effectively prevent sintering deformation. The present invention has high production efficiency, good green body quality, lower cost, and the prepared yttrium oxide ceramic has good wear resistance, high density and high strength.

[0018] (3) The present invention introduces low-frequency vibration during the grouting process, which can rearrange the yttrium oxide particles to achieve the densest packing to the maximum extent. In addition, the vibration can also remove the bubbles generated during the grouting process, so that the powder has a stronger sintering driving force and the ceramic is denser. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a SEM image of the yttrium oxide ceramic ring prepared in Example 4.

[0020] Figure 2 This is a physical picture of the yttrium oxide ceramic ring prepared in Example 4. DETAILED DESCRIPTION

[0021] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] Example 1

[0023] Step 1: First, 300g of yttrium oxide is dispersed in 1000g of anhydrous ethanol, and 15g of acrylic waterproof coating is added under stirring; then, the mixture is placed in a ball mill and milled with a ball-to-material ratio of 3:1; the ball milling time is 16h, and the mixture is dried at 50°C and passed through an 80-mesh sieve to obtain modified yttrium oxide powder;

[0024] Step 2: Add 96 g of deionized water, 2.5 g of dispersant ammonium citrate, 500 g of modified yttrium oxide powder, and 4 g of pH regulator tetramethylammonium hydroxide into a ball mill, mix and disperse to obtain a high solid content modified yttrium oxide slurry;

[0025] Step 3: After the modified yttrium oxide slurry is subjected to vacuum degassing, the vacuum degassing pressure is -0.8MPa, and the vacuum degassing time is 40min; under the conditions of a vibration frequency of 5Hz and a vibration time of 8h, the slurry is injected into a gypsum mold at a pressure of 0.5MPa to absorb water and dry, and then dried after demolding. The drying system is to dry in a constant temperature and humidity chamber at a humidity of 30% and a temperature of 35°C for 20h, and then dry at a temperature of 75-100°C for 15h to obtain a yttrium oxide ceramic body;

[0026] Step 4: Then heat the ceramic body in a muffle furnace at a rate of 1°C / min to 800°C and keep it for 1 hour. Heat it in a vacuum furnace at a rate of 1°C / min to 1250°C, and then heat it to 1800°C at a rate of 1°C / min and keep it for 2 hours. Finally, anneal the obtained ceramic in air at 1000°C for 3 hours to obtain yttrium oxide ceramic.

[0027] Example 2

[0028] Step 1: First, 350g of yttrium oxide is dispersed in 1000g of anhydrous ethanol, and 28g of silicone waterproof coating is added under stirring; then, the mixture is placed in a ball mill for ball milling, with a ball-to-material ratio of 2:1; the ball milling time is 20h, and the mixture is dried at 60°C and passed through a 100-mesh sieve to obtain modified yttrium oxide powder;

[0029] Step 2: 104 g of deionized water, 3.5 g of dispersant sodium polyacrylate, 500 g of modified yttrium oxide powder, and 6 g of pH regulator tetramethylammonium hydroxide were added to a ball mill and mixed and dispersed to obtain a high solid content modified yttrium oxide slurry;

[0030] Step 3: After the modified yttrium oxide slurry is subjected to vacuum degassing, the pressure of the vacuum degassing is -0.9MPa, and the vacuum degassing time is 30min; under the conditions of a vibration frequency of 15Hz and a vibration time of 6h, the slurry is injected into a gypsum mold at a pressure of 1MPa to absorb water and dry, and then dried after demolding. The drying system is to dry in a constant temperature and humidity chamber at a humidity of 35% and a temperature of 40°C for 18h, and then dry at a temperature of 80°C for 18h to obtain a yttrium oxide ceramic body;

[0031] Step 4: Then heat the ceramic body in a muffle furnace at a rate of 2°C / min to 800°C and keep it for 1.5 hours. Heat it in a vacuum furnace at a rate of 2°C / min to 1300°C, then heat it to 1810°C at a rate of 1.5°C / min and keep it for 4 hours. Finally, anneal the obtained ceramic in air at 1050°C for 2.5 hours to obtain yttrium oxide ceramic.

[0032] Example 3

[0033] Step 1: First, 400g of yttrium oxide was dispersed in 1000g of anhydrous ethanol, and 48g of epoxy resin waterproof coating was added under stirring; then, the mixture was placed in a ball mill and milled with a ball-to-material ratio of 1.5:1; the milling time was 16h, and the mixture was dried at 50°C and sieved with 80 mesh to obtain modified yttrium oxide powder;

[0034] Step 2: Add 181 g of deionized water, 5 g of polyethylene glycol as a dispersant, 500 g of modified yttrium oxide powder, and 7.5 g of tetramethylammonium hydroxide as a pH adjuster into a ball mill, mix and disperse to obtain a high solid content modified yttrium oxide slurry;

[0035] Step 3: After the modified yttrium oxide slurry is subjected to vacuum degassing, the pressure of the vacuum degassing is -1MPa, and the vacuum degassing time is 20min; under the conditions of a vibration frequency of 20Hz and a vibration time of 5h, the slurry is injected into a gypsum mold at a pressure of 1.5MPa to absorb water and dry, and then dried after demolding. The drying system is to dry in a constant temperature and humidity box at a humidity of 45% and a temperature of 45°C for 18h, and then dry at a temperature of 90°C for 15h to obtain a yttrium oxide ceramic body;

[0036] Step 4: Then heat the ceramic body in a muffle furnace at a rate of 4°C / min to 800°C and keep it warm for 1.5 hours. Heat it in a vacuum furnace at a rate of 2°C / min to 1325°C, and then heat it to 1840°C at a rate of 1.5°C / min and keep it warm for 3 hours. Finally, anneal the obtained ceramic in air at 1080°C for 2.5 hours to obtain yttrium oxide ceramic.

[0037] Example 4

[0038] Step 1: First, 500g of yttrium oxide is dispersed in 1000g of anhydrous ethanol, and 35g of acrylic waterproof coating and silicone waterproof coating are added under stirring; then, the mixture is placed in a ball mill for ball milling, and the ball-to-material ratio is 1:1; the ball milling time is 24h, and the mixture is dried at 80°C and passed through a 120-mesh sieve to obtain modified yttrium oxide powder;

[0039] Step 2: 125 g of deionized water, 3 g of dispersant ammonium citrate and sodium polyacrylate, 500 g of modified yttrium oxide powder, and 10 g of pH regulator tetramethylammonium hydroxide are added to a ball mill, mixed and dispersed to obtain a high solid content modified yttrium oxide slurry;

[0040] Step 3: After the modified yttrium oxide slurry is subjected to vacuum degassing, the pressure of the vacuum degassing is -0.9MPa, and the vacuum degassing time is 40min; under the conditions of a vibration frequency of 25Hz and a vibration time of 4h, the slurry is injected into a gypsum mold at a pressure of 2MPa to absorb water and dry, and then dried after demolding. The drying system is to dry in a constant temperature and humidity box with a humidity of 50% and a temperature of 35°C for 20h, and then dry at a temperature of 100°C for 15h to obtain a yttrium oxide ceramic body;

[0041] Step 4: Then heat the ceramic body in a muffle furnace at a rate of 3°C / min to 800°C and keep it for 2 hours. Heat it in a vacuum furnace at a rate of 5°C / min to 1350°C, and then heat it to 1850°C at a rate of 2°C / min and keep it for 5 hours. Finally, anneal the obtained ceramic in air at 1100°C for 3 hours to obtain yttrium oxide ceramic.

[0042] Figure 1 is a SEM image of the yttria ceramic ring prepared in this embodiment.

[0043] Figure 2 It is a physical picture of the yttrium oxide ceramic ring prepared in this embodiment.

[0044] Comparative Example

[0045] Step 1: First, 500g of yttrium oxide is dispersed in 1000g of anhydrous ethanol, and then placed in a ball mill for ball milling, with a ball-to-material ratio of 2:1; the ball milling time is 22h, and the yttrium oxide powder is obtained after drying at 80°C and passing through a 120-mesh sieve;

[0046] Step 2: 140 g of deionized water, 3.5 g of dispersant sodium polyacrylate, 500 g of modified yttrium oxide powder, and 6 g of pH regulator tetramethylammonium hydroxide were added to a ball mill and mixed and dispersed to obtain a high solid content modified yttrium oxide slurry;

[0047] Step 3: After the modified yttrium oxide slurry is subjected to vacuum degassing, the pressure of the vacuum degassing is -0.9MPa, and the vacuum degassing time is 30min; under the conditions of a vibration frequency of 15Hz and a vibration time of 6h, the slurry is injected into a gypsum mold at a pressure of 1MPa to absorb water and dry, and then dried after demolding. The drying system is to dry in a constant temperature and humidity chamber at a humidity of 35% and a temperature of 40°C for 18h, and then dry at a temperature of 80°C for 18h to obtain a yttrium oxide ceramic body;

[0048] Step 4: Then place the ceramic body in a muffle furnace, and then in the muffle furnace, heat it to 800°C at a rate of 2°C / min, and keep it warm for 1.5 hours. Heat it to 1300°C in a vacuum furnace at a rate of 2°C / min, and heat it to 1850°C at a rate of 1.5°C / min, and keep it warm for 5 hours. Finally, anneal the obtained ceramic in air at 1050°C for 2.5 hours to obtain yttrium oxide ceramics. The main difference between the comparative example and Examples 1-4 is that the unmodified yttrium oxide powder has a structural change due to hydrolysis, and the particles are severely agglomerated, which affects the dispersibility and reduces the solid content of the slurry; and more energy is required for sintering, which increases the production cost and cycle.

[0049] Effect verification:

[0050] The bending strength and density of the yttrium oxide ceramic materials obtained in the above-mentioned Examples 1, 2, 3 and 4 were tested according to the following standards. The test results are shown in Table 1.

[0051] Bending strength test: follow GB / T 6569-2006.

[0052] Density test: Archimedes drainage method was used to test sample density.

[0053] Table 1 Performance test results of yttrium oxide composite ceramics prepared in Examples 1-4

[0054] Example Strength (MPa) <![CDATA[Density (g / cm 3 )]]> Example 1 103 5.01 Example 2 105 5.06 Example 3 102 4.95 Example 4 106 5.02 Comparative Example 89 4.90

[0055] As shown in Table 1, the strength of the yttrium oxide ceramics prepared by the present invention exceeds 100 MPa and the density exceeds 4.9 g / cm 3 , indicating that it has higher strength and greater density, reflecting excellent mechanical properties.

[0056] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with the technical field within the technical scope disclosed by the present invention and within the spirit and principle of the present invention should be covered by the protection scope of the present invention.

Claims

1. A high performance yttria ceramic ring slurry casting method, characterized in that: The following steps are involved: Step 1: First, yttrium oxide is dispersed in anhydrous ethanol, and a polymer coating is added under stirring conditions, and then the mixture is placed in a ball mill for ball milling, and modified yttrium oxide powder is obtained after drying and sieving; Step 2: adding deionized water, dispersant, modified yttrium oxide powder, and pH adjuster tetramethylammonium hydroxide into a ball mill, mixing and dispersing, and obtaining a high solid content modified yttrium oxide slurry; Step 3: After vacuum degassing, the modified yttrium oxide slurry is injected into a gypsum mold under vibration conditions and pressure to absorb water and dry, and then demolded and dried to obtain an yttrium oxide ceramic body; Step 4: placing the ceramic body into a sintering furnace for sintering, and annealing to obtain yttrium oxide ceramics.

2. A high performance yttria ceramic ring slurry casting method according to claim 1, characterized in that: In step 1, the mass of yttrium oxide accounts for 30wt%-50wt% of anhydrous ethanol, the polymer coating is one or more of acrylic ester waterproof coating, silicone waterproof coating, epoxy resin waterproof coating, and the added amount is 5%-15% of the mass of yttrium oxide; the ball-to-material ratio is (1-3): 1; the ball milling time is 16-24h; dried at 50-80°C and passed through an 80-120 mesh sieve.

3. A high performance yttria ceramic ring slurry casting method according to claim 1, characterized in that: The dispersant in step 2 is one of ammonium citrate, sodium polyacrylate, and polyethylene glycol, and the amount of the dispersant added is 0.5%-1.2% of the modified yttrium oxide powder; the amount of the pH regulator tetramethylammonium hydroxide added is 0.8-2% of the modified yttrium oxide powder; and deionized water accounts for 16-20% of the total mass of the slurry.

4. A high performance yttrium oxide ceramic ring slurry casting method according to claim 1, characterized in that: In step three, the pressure of vacuum degassing is -0.8 to -1MPa, and the vacuum degassing time is 20-40min; the pressure of pressure grouting is 0.5-2MPa; the vibration frequency is 5-25Hz, and the vibration time is 4-8h; the specific process of drying after demoulding is: drying in a constant temperature and humidity chamber with a humidity of 30-50% and a temperature of 35-50°C for 15-20h, and then drying at a temperature of 75-100°C for 15-20h.

5. A high performance yttria ceramic ring slurry casting method according to claim 1, characterized in that: In step 4, the specific sintering process is as follows: in a muffle furnace, the temperature is raised to 800°C at a rate of 1-5°C / min, and kept at this temperature for 1-2 hours. In a vacuum furnace, the temperature is raised to 1250-1350°C at a rate of 1-3°C / min, and then to 1800-1850°C at a rate of 1-2°C / min, and kept at this temperature for 2-5 hours. Finally, the obtained ceramic is annealed in air at 1000-1100°C for 2-3 hours to obtain yttrium oxide ceramics.

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