Recrystallized silicon carbide ceramic tube and preparation method thereof

Abstract

The invention discloses a recrystallized silicon carbide ceramic tube. The recrystallized silicon carbide ceramic tube is prepared from silicon carbide powder comprising three components of recrystallized silicon carbide powder, 100F powder and powder with D50 of 20-25 microns through the processes of mixing, aging, pugging, extrusion forming, microwave drying and vacuum sintering. Compared with a two-component recrystallized silicon carbide ceramic, the multi-component silicon carbide powder can reach the maximum bulk density, so that the mechanical property of the recrystallized silicon carbide ceramic is improved. Compared with two-component recrystallized silicon carbide ceramics, the recrystallized silicon carbide ceramic tube prepared by the invention has the advantages that the high-temperature bending strength is averagely improved by 128 MPa, and the improvement rate is 177%; the compressive strength is averagely improved by 152MPa, and the improvement rate is 104%; the heat conductivity coefficient is averagely improved by 99W / m.K, and the improvement rate is 69%. And the material is especially suitable for key equipment in semiconductor and photovoltaic production processes. And the preparation process is mature and is beneficial to industrialization.

Description

Technical Field

[0001] The present invention belongs to the technical field of silicon carbide materials, and particularly relates to a recrystallized silicon carbide ceramic tube and a preparation method thereof. Background Art

[0002] In recent years, the photovoltaic and semiconductor industries have developed and expanded rapidly, driving the rapid development of many supporting industries. In particular, the demand for equipment components in the semiconductor and photovoltaic production processes has increased sharply. Since semiconductor key equipment is in direct contact with wafers, and even in some production processes, these equipment components are required to have high temperature resistance and a certain load-bearing capacity, so the material properties of these equipment components are relatively high. Silicon carbide ceramics are widely used in semiconductor equipment due to their high temperature stability, corrosion resistance, and good mechanical properties. Among them, recrystallized silicon carbide ceramics are better than pressureless and reaction-bonded silicon carbide ceramics in terms of thermal shock resistance and silicon carbide purity, and are more suitable for use as semiconductor equipment components. With more key components in semiconductor equipment using silicon carbide materials, the market demand for recrystallized silicon carbide ceramics will be increasing. Among them, recrystallized silicon carbide tubes, due to their high purity, good thermal shock resistance, and large thermal conductivity, are mainly used as transmission and load-bearing guides for wafers in high-temperature environments. Considering the special working conditions of this component, high temperatures above 1600 °C, a certain high-temperature load-bearing capacity, and high-purity silicon carbide materials, recrystallized silicon carbide tubes are used.

[0003] The development of the domestic recrystallized silicon carbide ceramic industry has been in a slow state of development and research due to the high price of recrystallized silicon carbide furnaces and the long-term influence of foreign 07 powder raw materials. Moreover, the quality of recrystallized silicon carbide ceramics is relatively poor, mostly low-end products, and cannot be applied to high-end fields. Therefore, it is urgent to develop a recrystallized silicon carbide ceramic tube with excellent mechanical properties and large thermal conductivity suitable for semiconductor key equipment. Summary of the Invention

[0004] Based on this, the present application provides a recrystallized silicon carbide ceramic tube and a preparation method thereof to solve the technical problems of poor mechanical properties and low thermal conductivity of recrystallized silicon carbide ceramic tubes in the prior art.

[0005] The technical solution of the present application to solve the above technical problems is as follows:

[0006] A preparation method of a recrystallized silicon carbide ceramic tube, comprising the following steps:

[0007] S10. Prepare raw materials according to the following weight parts: 15 to 25 parts of recrystallized silicon carbide powder, 50 25 to 35 parts of silicon carbide powder with a particle size of 20 - 25 μm, 40 to 60 parts of 100F powder, 6 to 9 parts of binder, 3 to 5 parts of plasticizer, 2 to 3 parts of lubricant, 4 to 6 parts of deionized water, and 1 to 2 parts of sintering aid;

[0008] S20. Put the raw materials in step S10 into a mixer, mix them thoroughly and evenly to obtain a mixture;

[0009] S30. Age and knead the mixture to obtain a recrystallized silicon carbide pipe blank;

[0010] S40. Extrude the recrystallized silicon carbide pipe blank to form a green pipe;

[0011] S50. Dry and vacuum sinter the green pipe to obtain a recrystallized silicon carbide ceramic pipe;

[0012] Among them, the particle size of the recrystallized silicon carbide powder is: D 10 is 0.3 - 0.45 μm, D 50 is 2.1 - 2.2 μm, D 90 is 6.5 - 8 μm;

[0013] The D 50 is 20 - 25 μm, and the particle size of the silicon carbide powder is: D 10 is 6 - 8 μm, D 50 is 20 - 25 μm, D 90 is 40 - 45 μm;

[0014] The particle size of the 100F powder is: D 10 is 45 - 55 μm, D 50 is 110 - 120 μm, D 90 is 220 - 230 μm.

[0015] Preferably, in the method for preparing the recrystallized silicon carbide ceramic pipe, the binder includes at least one of hydroxymethyl cellulose and phenolic resin.

[0016] Preferably, in the method for preparing the recrystallized silicon carbide ceramic pipe, the plasticizer is a mixture of polyethylene glycol and PVA, and the mass ratio of polyethylene glycol to PVA is (6 to 8):(4 to 2).

[0017] Preferably, in the method for preparing the recrystallized silicon carbide ceramic pipe, the lubricant is a mixture of glycerol and dibutyl phthalate, and the mass ratio of glycerol to dibutyl phthalate is (2 to 3):(3 to 2).

[0018] Preferably, in the method for preparing the recrystallized silicon carbide ceramic pipe, the sintering aid includes at least one of stearic acid, n-butanol, and n-octanol.

[0019] Preferably, in the method for preparing the recrystallized silicon carbide ceramic pipe, step S20 includes:

[0020] S21. Put the recrystallized silicon carbide powder, D50 20 - 25μm silicon carbide powder, 100F powder and a binder are added to a mixer and mixed thoroughly and evenly.

[0021] S22. The plasticizer, lubricant, deionized water and sintering aid are stirred in a water bath at 60 to 80 °C for 40 to 60 min, and then added to the mixer in step S21 for mixing to obtain the mixture.

[0022] Preferably, in the preparation method of the recrystallized silicon carbide ceramic tube, step S30 is specifically as follows: first, the mixture is subjected to the first aging, then pugged, and then subjected to the second aging to obtain the recrystallized silicon carbide clay.

[0023] Preferably, in the preparation method of the recrystallized silicon carbide ceramic tube, in step S50, the vacuum sintering includes pre-sintering and recrystallization sintering. Among them, the sintering temperature of the pre-sintering is 1100 to 1200 °C, and the heat preservation time is 1 to 2 hours; the sintering temperature of the recrystallization sintering is 2350 to 2500 °C, and the heat preservation time is 2 to 3 hours.

[0024] A recrystallized silicon carbide ceramic tube is prepared by using the preparation method of the recrystallized silicon carbide ceramic tube as described above.

[0025] Compared with the prior art, the present application has at least the following advantages:

[0026] The recrystallized silicon carbide ceramic tube disclosed in the present application is made of silicon carbide powder with three components of recrystallized silicon carbide powder, 100F powder, and D 50 powder of 20 - 25μm through processes of mixing, aging, pugging, extrusion forming, microwave drying and vacuum sintering. Using multi-component silicon carbide powder particles as ceramic raw materials, compared with the two-component recrystallized silicon carbide ceramic, the multi-component silicon carbide powder can achieve the maximum packing density, thereby improving the mechanical properties of the recrystallized silicon carbide ceramic. The recrystallized silicon carbide ceramic tube prepared in the present application, compared with the two-component recrystallized silicon carbide ceramic, has an average increase of 128 MPa in the high-temperature bending strength (1200 °C), with an increase rate of 177%; the compressive strength increases by an average of 152 MPa, with an increase rate of 104%; the thermal conductivity (room temperature) increases by an average of 99 W / m·K, with an increase rate of 69%. It has excellent mechanical properties and is especially suitable for key equipment in the semiconductor and photovoltaic production processes.

[0027] The recrystallized silicon carbide ceramic tube of the present application uses efficient plasticizers and lubricants in production, not only preparing a high-density recrystallized silicon carbide ceramic, but also reducing friction and the extrusion pressure during the extrusion forming process. The present application adopts the extrusion forming method, and the preparation process is mature, which is conducive to industrialization. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1This is the flowchart for preparing the recrystallized silicon carbide ceramic tube of the present application. Detailed implementation manners

[0029] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. The following will describe the technical solutions of the present invention in combination with the embodiments of the present invention. The present invention is not limited to the following specific implementation manners.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs. The terms used in the specification herein are only for the purpose of describing specific implementation manners and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0031] Please refer to Figure 1 , in a specific implementation manner of the present application, a method for preparing a recrystallized silicon carbide ceramic tube includes the following steps:

[0032] S10. Prepare raw materials according to the following parts by weight: 15 to 25 parts of recrystallized silicon carbide powder, D 50 Silicon carbide powder with D of 20 - 25μm: 25 to 35 parts, 100F powder: 40 to 60 parts, binder: 6 to 9 parts, plasticizer: 3 to 5 parts, lubricant: 2 to 3 parts, deionized water: 4 to 6 parts, sintering aid: 1 to 2 parts;

[0033] Among them, the particle size of the recrystallized silicon carbide powder is: D 10 At 0.3 - 0.45μm, D 50 At 2.1 - 2.2μm, D 90 At 6.5 - 8μm;

[0034] The D 50 Silicon carbide powder with D of 20 - 25μm has a particle size of: D 10 At 6 - 8μm, D 50 At 20 - 25μm, D 90 At 40 - 45μm;

[0035] The particle size of the 100F powder is: D 10 At 45 - 55μm, D 50 At 110 - 120μm, D 90 At 220 - 230μm;

[0036] In the present application, multi-component silicon carbide powder particles are used to form ceramic raw materials. Among them, the performance parameters of the recrystallized silicon carbide powder are: particle size: D 10 At 0.3 - 0.45μm, D 50 At 2.1 - 2.2μm, D90 At 6.5 - 8 μm; specific surface area: 6 - 7 m 2 / g, pH: 4 - 5, tapped density: 1.1 - 1.25 g / cm 3 , bulk density: 0.6 - 0.9 g / cm 3 ; The performance parameters of the D 50 20 - 25 μm silicon carbide powder are: particle size: D 10 At 6 - 8 μm, D 50 At 20 - 25 μm, D 90 At 40 - 45 μm, pH: 6 - 8; tapped density: 1.6 - 1.8 g / cm 3 , bulk density: 1.2 - 1.4 g / cm 3 ; The performance parameters of the 100F powder are: particle size: D 10 At 45 - 55 μm, D 50 At 110 - 120 μm, D 90 At 220 - 230 μm, pH: 6 - 8; tapped density: 1.8 - 2 g / cm 3 , bulk density: 1.5 - 1.6 g / cm 3 . Compared with the two - component recrystallized silicon carbide ceramics, the multi - component silicon carbide powder can achieve the maximum packing density, thereby improving the mechanical properties of the recrystallized silicon carbide ceramics. The recrystallized silicon carbide ceramic tube prepared in this application has a high - temperature bending strength (1200 °C) of 200 MPa, a compressive strength of 298 MPa, and a thermal conductivity (room temperature) of 243 W / m·K. Compared with the two - component recrystallized silicon carbide ceramics of Comparative Examples 1 to 3, the high - temperature bending strength (1200 °C) is increased by an average of 128 MPa, with an increase rate of 177%; the compressive strength is increased by an average of 152 MPa, with an increase rate of 104%; the thermal conductivity (room temperature) is increased by an average of 99 W / m·K, with an increase rate of 69%. It has excellent mechanical properties and is particularly suitable for semiconductor key equipment. It should be noted that the above - mentioned binder, plasticizer, lubricant, and sintering aid are all organic aids.

[0037] In one embodiment, the binder includes at least one of hydroxymethyl cellulose and phenolic resin, and hydroxymethyl cellulose is preferably selected in this application.

[0038] In one embodiment, the plasticizer is a mixture of polyethylene glycol and PVA, and the mass ratio of the polyethylene glycol to the PVA is (6 to 8):(4 to 2). Further, the mass ratio of the polyethylene glycol to the PVA is 7:3.

[0039] In one embodiment, the lubricant is a mixture of glycerol and dibutyl phthalate, and the mass ratio of glycerol to dibutyl phthalate is (2 to 3):(3 to 2). Further, the mass ratio of glycerol to dibutyl phthalate is 1:1.

[0040] Recrystallized silicon carbide ceramics are usually made by mixing two kinds of coarse powder and fine powder in a certain proportion as raw materials. The coarse powder is mostly particle powder above 100μm, which will cause great friction between powder particles and between the material and the extruder during the extrusion forming process. The extrusion pressure is high, and it is extremely easy to cause damage to the extrusion equipment. This solution uses highly efficient plasticizers and lubricants, not only preparing high-density recrystallized silicon carbide ceramics, but also reducing friction and lowering the extrusion pressure.

[0041] In one embodiment, the sintering aid includes at least one of stearic acid, n-butanol, and n-octanol. In this application, stearic acid is preferably used.

[0042] S20. Put the raw materials in step S10 into a mixer, mix them thoroughly and evenly to obtain a mixture. Further, step S20 includes: S21. Put the recrystallized silicon carbide powder, D 50 Silicon carbide powder with a particle size of 20 - 25μm, 100F powder and the binder into the mixer and mix them thoroughly and evenly; S22. Water bath stir the plasticizer, lubricant, deionized water and sintering aid at 60 to 80°C for 40 to 60 minutes, and then add them to the mixer in step S21 to carry out mixing to obtain the mixture.

[0043] For example, put 15 to 25 parts of the above-mentioned recrystallized silicon carbide powder, D 50 Silicon carbide powder with a particle size of 20 - 25μm, 25 to 35 parts, 100F powder 40 to 60 parts, into the mixer, mix at a barrel rotation speed of 10 rad / min and a stirring paddle rotation speed of 20 rad / min for 30 - 45 minutes, add 6 to 9 parts of the binder and continue to mix for 30 - 45 minutes to make the silicon carbide powders with different particle sizes and the binder mix thoroughly and evenly with each other; Water bath stir 3 to 5 parts of the plasticizer, 2 to 3 parts of the lubricant, 4 to 6 parts of deionized water, and 1 to 2 parts of the sintering aid in a water bath at 60 - 80°C for 40 - 60 minutes, and pour the mixed solution into the mixer to make the solution uniformly disperse and wrap on the surface of the silicon carbide powder particles, and finally obtain a mixture of silicon carbide powder and organic additives (plasticizer, lubricant, sintering aid).

[0044] S30. Carry out aging and pugging on the mixture to obtain the recrystallized silicon carbide tube stock.

[0045] Specifically, first, the mixture is subjected to the first aging process, then pugged, and next, it undergoes the second aging process to obtain the recrystallized silicon carbide clay material. For example, in the first aging process: the above mixture is wrapped and sealed after exhausting the air with a plastic bag, and placed in an environment with a temperature of 20 - 30°C and a humidity of 40% - 60% for 20 - 24 hours to allow the organic additives, water, and powder to be fully fused again. Pugging: The aged recrystallized silicon carbide pipe clay material is repeatedly extruded and pugged 4 - 6 times through a vacuum pug mill at a vacuum degree of 0.05 - 0.1 MPa and a pressure of 40 - 60 MPa to eliminate the gas and defects in the clay material, making the clay material more uniform and dense. In the second aging process: the pugged recrystallized silicon carbide pipe clay material is continuously placed in a sealed plastic bag and aged in an environment with a temperature of 20 - 30°C and a humidity of 40% - 60% for 20 - 30 hours to form a recrystallized silicon carbide clay material with good plasticity and uniform material.

[0046] S40. Extrude and form the recrystallized silicon carbide pipe clay material to obtain a green body pipe; specifically, the recrystallized silicon carbide clay material is extruded into a green body pipe of the required specification through a vacuum screw extruder.

[0047] S50. Dry and vacuum sinter the green body pipe to obtain a recrystallized silicon carbide ceramic pipe.

[0048] The drying process directly affects the tube deformation, surface defects, etc. during the sintering process. To ensure the uniform drying of the inside and outside of the recrystallized silicon carbide green body pipe, first, a microwave drying process is used for low-temperature drying. The low-temperature drying temperature is set at 50 - 70°C, and the time is 40 - 60 minutes. Then, the green body pipe is placed in an oven and dried with forced hot air. The drying temperature is set at 80 - 100°C, and the time is 120 - 240 minutes.

[0049] Preferably, the vacuum sintering includes pre-sintering and recrystallization sintering. Among them, the sintering temperature of the pre-sintering is 1100 to 1200°C, and the heat preservation time is 1 to 2 hours; the sintering temperature of the recrystallization sintering is 2350 to 2500°C, and the heat preservation time is 2 to 3 hours. Specifically, the dried recrystallized silicon carbide green body pipe is placed in a graphite U-shaped groove in a non-pressure sintering furnace for pre-sintering to completely remove the organic additives in the recrystallized silicon carbide pipe. The sintering temperature is 1100 - 1200°C, and the heat preservation time is 1 - 2 hours; then, it is placed in a vacuum induction sintering furnace for recrystallization sintering. The sintering temperature is 2350 - 2500°C, and the heat preservation time is 2 - 3 hours.

[0050] In another specific embodiment of the present application, a recrystallized silicon carbide ceramic pipe is obtained by using the method for preparing a recrystallized silicon carbide ceramic pipe as described above.

[0051] It should be noted that the process temperature and process time involved in the above embodiments are a temperature or time adopted during the experiment. Those skilled in the art can make reasonable adjustments within the error range based on the process temperature and process time provided by the present invention, and all such adjustments should be included within the protection scope of the present invention; the dispersant, organic auxiliary agent, and sintering auxiliary agent are preferred embodiments of the present invention and can be used alone or in combination, or other alternative solutions can also be selected.

[0052] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail through experimental examples below.

[0053] Experimental materials:

[0054] The recrystallized silicon carbide powder, silicon carbide powder with D50 of 20 - 25μm, and 100F powder are from Ningxia Northern High-Tech Industry Co., Ltd. Other preparations involved in the present invention are all standard preparations that can be purchased on the market.

[0055] Performance test methods and instruments:

[0056] The performance tests are carried out according to the GB / T national standard. The fracture toughness and flexural strength of the recrystallized silicon carbide ceramic tube are detected by a universal testing machine; the compressive strength of the recrystallized silicon carbide ceramic tube is detected by a compressive testing machine; and the thermal conductivity of the recrystallized silicon carbide ceramic tube is detected by a linear dilatometer.

[0057] Comparative example

[0058] Preparation of the recrystallized silicon carbide tube:

[0059] Batching and mixing of the recrystallized silicon carbide tube mud: Put the recrystallized silicon carbide powder, silicon carbide powder with D50 of 20 - 25μm, and 100F powder into a mixer according to the addition amounts shown in Table 1, and mix for 40 min at a barrel rotation speed of 10 rad / min and a stirring paddle rotation speed of 20 rad / min. Then add 7 parts of carboxymethyl cellulose (binder) and continue mixing for 40 min to make the silicon carbide powders with different particle sizes and the binder fully and evenly mixed. Stir 4 parts of polyethylene glycol and PVA (plasticizer, with a weight ratio of polyethylene glycol to PVA of 7:3, that is, 2.8 parts of polyethylene glycol and 1.2 parts of PVA), a mixture of 2.5 parts of glycerol and dibutyl phthalate (where 1.25 parts of glycerol and 1.25 parts of dibutyl phthalate), 5 parts of deionized water, and 1.5 parts of stearic acid in a 70°C water bath for 50 min, and pour this mixed solution into the mixer to make the solution evenly disperse and coat the surface of the silicon carbide powder particles. Finally, a mixture of silicon carbide powder and organic auxiliary agent is obtained.

[0060] Storing and Kneading the Material for Recrystallized Silicon Carbide Tubes: Wrap the above mixture with a plastic bag after evacuating the air, seal it, and place it in an environment with a temperature of 25°C and a humidity of 50% for 22 hours of storage, allowing the organic additives, water, and powder to fully blend again. Knead the stored material for recrystallized silicon carbide tubes 5 times through a vacuum kneader at a vacuum degree of 0.8 MPa and a pressure of 50 MPa to eliminate the gas and defects in the material, making the material more uniform and dense. Continue to place the kneaded material for recrystallized silicon carbide tubes in a sealed plastic bag and store it in an environment with a temperature of 25°C and a humidity of 50% for 25 hours to form a recrystallized silicon carbide material with good plasticity and uniform material.

[0061] Extrusion Molding of the Material for Recrystallized Silicon Carbide Tubes: Extrude the recrystallized silicon carbide material through a vacuum screw extruder to form a green tube with a length of 1.5 m, a pipe diameter of 18 cm, and a wall thickness of 3 cm.

[0062] Drying, Vacuum Pre-sintering, and Sintering of the Recrystallized Silicon Carbide Green Tubes: The drying process directly affects the tube deformation and surface defects during the sintering process. To ensure the uniform drying of the inside and outside of the recrystallized silicon carbide green tubes, first use the microwave drying process for low-temperature drying. The low-temperature drying temperature is set at 60°C and the time is 50 minutes. Then place the green tubes in an oven and use forced-air high-temperature drying. The drying temperature is set at 90°C and the time is 200 minutes. After drying, place the recrystallized silicon carbide green tubes in a graphite U-shaped groove in a non-pressure sintering furnace for pre-sintering to completely remove the organic additives in the recrystallized silicon carbide tubes. The sintering temperature is 1150°C and the holding time is 1.5 hours. Then place them in a vacuum induction sintering furnace for recrystallization sintering. The sintering temperature is 2450°C and the holding time is 2.5 hours to obtain recrystallized silicon carbide ceramic tubes.

[0063] Table 1 Raw Material Table of the Comparative Example

[0064] Name Comparative Example 1 Comparative Example 2 Comparative Example 3 Recrystallized silicon carbide powder / part 0 25 25 Silicon carbide powder with D50 of 20 - 25μm / part 40 0 75 100F powder / part 60 75 0 Hydroxymethyl cellulose / part 7 7 7 Polyethylene glycol and PVA / part 4 4 4 Glycerol and dibutyl phthalate / part 2.5 2.5 2.5 Deionized water / part 5 5 5 Stearic acid / part 1.5 1.5 1.5

[0065] Performance Testing: Conduct performance testing on the prepared recrystallized silicon carbide ceramic tubes. The test results are shown in Table 2.

[0066] Table 2 Indexes of the Recrystallized Silicon Carbide Ceramic Tubes of the Comparative Example

[0067] Name Comparative Example 1 Comparative Example 2 Comparative Example 3 High temperature bending strength (1200℃) (MPa) 67 74 75 Compressive strength (MPa) 139 152 147 Thermal conductivity (room temperature) (W / m·K) 155 132 146

[0068] As can be seen from the above table, when any two of the recrystallized silicon carbide powder, silicon carbide powder with a D50 of 20 - 25 μm, and 100F powder are mixed to form the ceramic raw materials, the mechanical properties and the guiding thermal coefficient of the prepared recrystallized silicon carbide ceramic tubes are not ideal enough and are not suitable for key equipment in semiconductor production.

[0069] Experiment 1: Exploring the Influence of Three Components of Silicon Carbide Powder on the Performance of Silicon Carbide Ceramic Tubes

[0070] The preparation method of the recrystallized silicon carbide tube is the same as that of the comparative example, except that silicon carbide powder with three components is used, and the addition amounts are shown in Table 3:

[0071] Table 3 Raw materials for Experiment 1

[0072]

[0073]

[0074] Performance test: The performance of the prepared recrystallized silicon carbide ceramic tube was tested, and the test results are shown in Table 4.

[0075] Table 4 Indexes of the recrystallized silicon carbide ceramic tube in the comparative example

[0076]

[0077] It can be seen from the above table that when other condition parameters remain unchanged, the performance of the silicon carbide ceramic tube prepared with silicon carbide powder with three components has been significantly improved compared with the three groups of comparative examples. Among them, the average high-temperature bending strength has increased by 64 MPa, the average compressive strength has increased by 85 MPa, and the average thermal conductivity has increased by 61 W / (m·K). In particular, the performance indexes of Example 4 are the highest. The high-temperature bending strength reaches 200 MPa, the compressive strength reaches 298 MPa, and the thermal conductivity is as high as 243 W / (m·K). Compared with the two-component recrystallized silicon carbide ceramics in Comparative Examples 1 to 3, the average high-temperature bending strength (at 1200 °C) has increased by 128 MPa, with an increase rate of 177%; the average compressive strength has increased by 152 MPa, with an increase rate of 104%; the average thermal conductivity (at room temperature) has increased by 99 W / (m·K), with an increase rate of 69%.

[0078] Experiment 2: Explore the influence of the addition amount of the binder on the performance of the silicon carbide ceramic tube

[0079] The preparation method of the recrystallized silicon carbide tube is the same as that of Example 4, except that the addition amount of sodium carboxymethyl cellulose is different, as shown in Table 5 for details:

[0080] Table 5 Raw materials for Experiment 2

[0081]

[0082]

[0083] Performance test: The performance of the prepared recrystallized silicon carbide ceramic tube was tested, and the test results are shown in Table 6.

[0084] Table 6 Indexes of the recrystallized silicon carbide ceramic tube in Experiment 2

[0085]

[0086] Please refer to Table 6. When other condition parameters remain unchanged and only the addition amount of hydroxymethylcellulose is changed, the mechanical properties of the prepared recrystallized silicon carbide ceramic tubes also vary. Among them, the mechanical properties of Examples 10 to 12 are relatively excellent. By combining and comparing with the performance indexes of Example 4, it can be concluded that when other condition parameters remain unchanged and the addition amount of hydroxymethylcellulose is 5 parts to 9 parts, the mechanical properties of the prepared recrystallized silicon carbide ceramic tubes are good. Among them, in Example 4, that is, when the addition amount of hydroxymethylcellulose is 7 parts, the mechanical properties of the recrystallized silicon carbide ceramic tubes are the most excellent.

[0087] Experiment 3: Explore the influence of the addition amount of plasticizer on the performance of silicon carbide ceramic tubes

[0088] The preparation method of the recrystallized silicon carbide tubes is the same as that of Example 4, except that the total addition amount of polyethylene glycol and PVA is different (the weight ratio of polyethylene glycol to PVA is 7:3). See Table 7 for details:

[0089] Table 7 Raw materials table for Experiment 3

[0090]

[0091]

[0092] Performance test: Perform performance tests on the prepared recrystallized silicon carbide ceramic tubes, and the test results are shown in Table 8.

[0093] Table 8 Indexes of recrystallized silicon carbide ceramic tubes in Experiment 3

[0094]

[0095] Please refer to Table 8. When other condition parameters remain unchanged and only the total addition amount of polyethylene glycol and PVA is changed and the weight ratio of polyethylene glycol to PVA is 7:3, and the total addition amounts of polyethylene glycol and PVA are 3 parts and 5 parts respectively, the compressive strength and thermal conductivity of the prepared recrystallized silicon carbide ceramic tubes are relatively excellent, but the high-temperature bending strength is slightly lower. It can be seen that compared with the total addition amounts of polyethylene glycol and PVA in Example 4 being 4 parts respectively, the comprehensive mechanical properties of the recrystallized silicon carbide ceramic tubes in Example 14 and Example 15 are inferior to those in Example 4. That is to say, when the total addition amounts of polyethylene glycol and PVA are 4 parts respectively and their mass ratio is 7:3, the comprehensive mechanical properties of the prepared recrystallized silicon carbide ceramic tubes are the best.

[0096] Experiment 4: Explore the influence of the ratio of polyethylene glycol to PVA on the performance of silicon carbide ceramic tubes

[0097] The preparation method of the recrystallized silicon carbide tube is the same as that of Example 4, except that the total addition amount of polyethylene glycol and PVA is the same, but the weight ratio between the two is different. See Table 9 for details:

[0098] Table 7 Raw Materials Table for Experiment 4

[0099]

[0100]

[0101] Performance Test: The performance of the prepared recrystallized silicon carbide ceramic tube was tested, and the test results are shown in Table 10.

[0102] Table 10 Indexes of Recrystallized Silicon Carbide Ceramic Tube for Experiment 4

[0103]

[0104] As can be seen from Table 10, in Examples 16 to 17, when other condition parameters remain unchanged and the total addition amount of polyethylene glycol and PVA is 4 parts, by changing the mass ratio between the two, the mechanical properties of the prepared recrystallized silicon carbide ceramic tubes are not very different, but they are all significantly lower than those of Example 4 (the mass ratio of polyethylene glycol and PVA is 7:3). This shows that under the condition of a certain total addition amount, when the mass ratio of polyethylene glycol and PVA is 7:3, the mechanical properties of the prepared recrystallized silicon carbide ceramic tube are the best.

[0105] Experiment 5: Explore the Influence of the Addition Amount of Lubricant on the Performance of Silicon Carbide Ceramic Tube

[0106] The preparation method of the recrystallized silicon carbide tube is the same as that of Example 4, except that the total addition amounts of glycerol and dibutyl phthalate are different (the weight ratio of glycerol and dibutyl phthalate is 1:1). See Table 11 for details:

[0107] Table 11 Raw Materials Table for Experiment 5

[0108]

[0109]

[0110] Performance Test: The performance of the prepared recrystallized silicon carbide ceramic tube was tested, and the test results are shown in Table 12.

[0111] Table 12 Indexes of Recrystallized Silicon Carbide Ceramic Tube for Experiment 5

[0112]

[0113] As can be seen from Table 11, when other condition parameters remain unchanged and only the total addition amount of glycerol and dibutyl phthalate is changed with the weight ratio of glycerol to dibutyl phthalate being 1:1, the mechanical properties of the recrystallized silicon carbide ceramic tubes prepared are not very different. However, compared with Example 4 (total addition amount of glycerol and dibutyl phthalate being 2.5 parts), the gap is still relatively large. The high-temperature flexural strength of Example 4 is 38 MPa higher than that of Example 20 and 15 MPa higher than that of Example 21; the compressive strength is 14 MPa higher than that of Example 20 and 13 MPa higher than that of Example 21; the thermal conductivity is 22 W / m·K higher than that of Example 20 and 16 W / m·K higher than that of Example 21. Thus, it can be seen that when the total addition amount of glycerol and dibutyl phthalate is 2.5 parts and the weight ratio of glycerol to dibutyl phthalate is 1:1, the comprehensive mechanical properties of the recrystallized silicon carbide ceramic tubes prepared are optimal.

[0114] Experiment 6: Exploring the Influence of the Ratio of Glycerol to Dibutyl Phthalate on the Properties of Silicon Carbide Ceramic Tubes

[0115] The preparation method of the recrystallized silicon carbide tubes is the same as that of Example 4, except that the total addition amount of glycerol and dibutyl phthalate is the same, but their weight ratios are different. See Table 13 for details:

[0116] Table 13 Raw Materials Table for Experiment 6

[0117]

[0118]

[0119] Performance Test: Perform performance tests on the prepared recrystallized silicon carbide ceramic tubes, and the test results are shown in Table 14.

[0120] Table 14 Indexes of Recrystallized Silicon Carbide Ceramic Tubes in Experiment 6

[0121]

[0122] Please refer to Table 14. For the recrystallized silicon carbide ceramic tubes of Examples 22 to 25, the average high-temperature flexural strength is 166 MPa, the average compressive strength is 267 MPa, and the average thermal conductivity is 225 W / m·K. That is to say, when other condition parameters remain unchanged and the total addition amount of glycerol and dibutyl phthalate is 2.5 parts, changing their mass ratios (2:3 for Example 22, 3:2 for Example 23, and single components for Examples 24 and 25) results in significantly lower mechanical properties of the recrystallized silicon carbide ceramic tubes than those of Example 4 (mass ratio of glycerol to dibutyl phthalate being 1:1). This shows that under the condition of a certain total addition amount, the mechanical properties of the recrystallized silicon carbide ceramic tubes are optimal when the mass ratio of glycerol to dibutyl phthalate is 1:1.

[0123] In summary, when preparing the recrystallized silicon carbide ceramic tube of the present application, the raw materials are prepared according to the following parts by weight: 15 to 25 parts of recrystallized silicon carbide powder, D 50 25 to 35 parts of 20-25μm silicon carbide powder, 40 to 60 parts of 100F powder, 6 to 9 parts of binder, 3 to 5 parts of plasticizer, 2 to 3 parts of lubricant, 4 to 6 parts of deionized water, 1 to 2 parts of sintering aid; then through processes such as mixing, aging, pugging, extrusion molding, drying, and vacuum sintering, the obtained recrystallized silicon carbide ceramic tube has a high-temperature bending strength (1200°C) of 200 MPa, a compressive strength of 298 MPa, and a thermal conductivity (room temperature) of 243 W / m·K. Compared with the two-component recrystallized silicon carbide ceramic, the high-temperature bending strength (1200°C) is increased by an average of 128 MPa, with an increase rate of 177%; the compressive strength is increased by an average of 152 MPa, with an increase rate of 104%; the thermal conductivity (room temperature) is increased by an average of 99 W / m·K, with an increase rate of 69%. It has excellent mechanical properties and is particularly suitable for key equipment in the semiconductor and photovoltaic production processes.

[0124] The above embodiments only represent several implementation manners of the present application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

Claims

1. A preparation method of a recrystallized silicon carbide ceramic tube, characterized in that, It includes the following steps: S10. Prepare raw materials according to the following parts by weight: 15 to 25 parts of recrystallized silicon carbide powder, 50 25 to 35 parts of silicon carbide powder with a particle size of 20 - 25 μm, 40 to 60 parts of 100F powder, 6 to 9 parts of binder, 3 to 5 parts of plasticizer, 2 to 3 parts of lubricant, 4 to 6 parts of deionized water, and 1 to 2 parts of sintering aid; S20. Put the raw materials in step S10 into a mixer, mix them thoroughly and evenly to obtain a mixture; S30. Age and knead the mixture to obtain a recrystallized silicon carbide tube blank; S40. Extrude and form the recrystallized silicon carbide tube blank to obtain a green tube; S50. Dry and vacuum sinter the green tube to obtain a recrystallized silicon carbide ceramic tube; Among them, the particle size of the recrystallized silicon carbide powder is: D 10 is in the range of 0.3 - 0.45 μm, D 50 is in the range of 2.1 - 2.2 μm, D 90 is in the range of 6.5 - 8 μm; The said D 50 is silicon carbide powder with a particle size of 20 - 25μm: D 10 is at 6 - 8μm, D 50 is at 20 - 25μm, D 90 is at 40 - 45μm; The particle size of the 100F powder is: D 10 is between 45 - 55 μm, D 50 is between 110 - 120 μm, D 90 is between 220 - 230 μm.

2. The preparation method of the recrystallized silicon carbide ceramic tube according to claim 1, characterized in that, The binder includes at least one of hydroxy methyl cellulose and phenolic resin.

3. The preparation method of the recrystallized silicon carbide ceramic tube according to claim 1, wherein, The plasticizer is a mixture of polyethylene glycol and PVA, and the mass ratio of polyethylene glycol to PVA is (6 to 8):(4 to 2).

4. The preparation method of the recrystallized silicon carbide ceramic tube according to claim 1, characterized in that, The lubricant is a mixture of glycerol and dibutyl phthalate, and the mass ratio of glycerol to dibutyl phthalate is (2 to 3):(3 to 2).

5. The preparation method of the recrystallized silicon carbide ceramic tube according to claim 1, characterized in that, The sintering aid includes at least one of stearic acid, n-butanol, and n-octanol.

6. The preparation method of the recrystallized silicon carbide ceramic tube according to claim 1, characterized in that, Step S20 includes: S21. Add recrystallized silicon carbide powder, D 50 Silicon carbide powder with a particle size of 20 - 25μm, 100F powder and a binder into a mixer and mix them evenly; S22. Stir the plasticizer, lubricant, deionized water, and sintering aid in a water bath at 60 to 80 °C for 40 to 60 min, and then add them to the mixer in step S21 for mixing to obtain the mixture.

7. The preparation method of the recrystallized silicon carbide ceramic tube according to claim 1, characterized in that, Step S30 is specifically to first age the mixture, then knead it, and then age it again to obtain a recrystallized silicon carbide blank.

8. The method for preparing a recrystallized silicon carbide ceramic tube according to claim 1, wherein, In step S50, the vacuum sintering includes pre-sintering and recrystallization sintering. Among them, the sintering temperature of the pre-sintering is 1100 to 1200 °C, and the heat preservation time is 1 to 2 hours; the sintering temperature of the recrystallization sintering is 2350 to 2500 °C, and the heat preservation time is 2 to 3 hours.

9. A recrystallized silicon carbide ceramic tube, characterized in that, It is prepared by using the preparation method of the recrystallized silicon carbide ceramic tube according to any one of claims 1 to 8.

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