High-precision quartz crucible and preparation and repair process thereof

Abstract

The invention discloses a high-precision quartz crucible and a preparation and repair process thereof, and relates to the technical field of crucible preparation, the preparation steps are as follows: S1, preparing materials including 100-700 parts of refractory clay, 20-500 parts of quartz sand, 10-300 parts of manganese dioxide, 20-450 parts of a silicon nitride coating, 10-100 parts of carbon nanotubes, 10-30 parts of a binder, 20-50 parts of a stabilizer, 20-60 parts of a cosolvent and 10-20 parts of a modifier; s2, weighing the materials in proportion, and mixing the refractory clay, manganese dioxide and quartz sand to obtain a mixture; putting the carbon nano tube into absolute ethyl alcohol; the carbon nanotubes are subjected to ultrasonic dispersion to form an enhanced network, so that the protective property is improved, and the service life is prolonged by 30% or above; a high-precision mold and dust-free finishing are matched, so that the defect rate is effectively reduced; the material selection effect and cost are both considered, the process is adaptive to an existing production line, mass production can be achieved without large-scale transformation, and the product has the comprehensive performance of high temperature resistance and thermal shock resistance and is widely applied to high-precision scenes of semiconductors, photovoltaics and special smelting.

Description

Technical Field

[0001] This invention relates to the field of crucible preparation technology, specifically to high-precision quartz crucibles and their preparation and repair processes. Background Technology

[0002] Quartz crucibles, due to their high temperature resistance, strong chemical stability, and low coefficient of thermal expansion, are core components in fields such as semiconductor silicon single crystal pulling, photovoltaic cell production, and special alloy smelting. As semiconductor chip manufacturing processes advance towards the nanometer scale and photovoltaic module efficiency requirements increase, more stringent requirements are placed on the precision (dimensional error ≤ ±0.05 mm), density (≥96%), high temperature resistance (long-term operating temperature ≥1600℃), and thermal shock resistance of quartz crucibles. However, materials in traditional formulations in existing technologies cannot effectively utilize the performance of quartz crucibles, and their poor high-temperature resistance leads to cracks and defects during use, making it difficult to meet the mechanical performance requirements of high-precision applications. To address this, we propose a high-precision quartz crucible and its preparation and repair process. Summary of the Invention

[0003] To solve the above-mentioned technical problems, this technical solution provides a high-precision quartz crucible and its preparation and repair process, thus solving the aforementioned problems.

[0004] To achieve the above objectives, the technical solution adopted in this invention is: a preparation process for a high-precision quartz crucible, comprising the following steps: S1. Prepare materials, including: 100-700 parts of refractory clay, 20-500 parts of quartz sand, 10-300 parts of manganese dioxide, 20-450 parts of silicon nitride coating, 10-100 parts of carbon nanotubes, 10-30 parts of binder, 20-50 parts of stabilizer, 20-60 parts of co-solvent, and 10-20 parts of modifier; S2. Weigh the materials according to the proportion, mix the refractory clay, manganese dioxide and quartz sand to obtain a mixture; put the carbon nanotubes into anhydrous ethanol and perform ultrasonic dispersion treatment to obtain a carbon nanotube dispersion; mix the mixture and the carbon nanotube dispersion and stir; add binder, stabilizer, cosolvent and modifier during stirring to continuously adjust the viscosity of the slurry. S3. Select a stainless steel mold, coat the inner wall of the mold with a release agent, and use the vacuum injection method to inject the slurry into the mold to remove air bubbles in the slurry. Let it stand for 2-4 hours until the material has initially solidified, and then demold it. Place the demolded blank in a dust-free workshop to trim the outer wall. S4. Perform drying treatment: dry the embryos at room temperature with ventilation for 12 hours and then heat them at a gradient of 50-120℃. S5. Firing: Preheat the temperature to 400-600℃ for pre-firing and degreasing. After completion, heat the temperature to 1650-1750℃ under nitrogen protection for high-temperature sintering and hold for 3-5 hours. S6. Remove the blank, spray silicon nitride coating on the outer surface and fire and cure it; remove it and perform subsequent grinding and polishing to obtain a quartz crucible.

[0005] Preferably, in step S1, the binder is one of water glass, alumina molten adhesive, and polyvinyl alcohol; the stabilizer is one of calcium oxide, magnesium oxide, and zirconium oxide; the co-solvent is one of borax, boric acid, and calcium fluoride; and the modifier is one of silane coupling agent, titanate coupling agent, and polyethylene glycol.

[0006] Preferably, in step S2, a planetary mixer is used for mixing, and the mixture is dry-mixed at 250 r / min for 40 min, with the wall scraped every 10 min to obtain a uniform mixture; the ultrasonic dispersion time is 30 min and the frequency is 40 kHz; the dispersion is injected into the mixture, and the speed is adjusted to 180 r / min for 20 min; the viscosity is monitored in real time by a rotational viscometer, and the viscosity is adjusted by adding anhydrous ethanol or dry mixture.

[0007] Preferably, in step S3, the vacuum grouting method involves injecting the grout into the mold at a rate of 5-10 mL / s, maintaining a vacuum of -0.08 MPa for 30 minutes to remove air bubbles, and then allowing it to stand in a cleanroom at 25±2℃ and 50-60% humidity for 2-4 hours for initial curing. After demolding, the outer wall flash is trimmed with a diamond scraper, and imperfections are polished.

[0008] Preferably, in step S4, the trimmed blanks are placed in layers on a breathable tray with a spacing of ≥5cm; they are ventilated and dried for 12 hours, during which the blanks are turned over once every 4 hours; after completion, they are transferred to a drying oven, and a gradient heating program is started, raising the temperature from 50℃ to 80℃ at a rate of 5℃ / h and holding for 2 hours; then the temperature is raised to 120℃ at the same rate and held for 4 hours, keeping the humidity inside the oven ≤30%.

[0009] Preferably, in step S5, the pre-calcination degreasing temperature is increased from room temperature to 400-600℃ at a rate of 5℃ / min, and then held for 2 hours after reaching the set temperature. The complete decomposition of organic matter is confirmed by monitoring the exhaust gas in the kiln (degreasing rate ≥98%). During this period, the situation inside the kiln is observed in real time to prevent local overheating from causing deformation of the green body. After degreasing is completed, nitrogen gas is introduced for high-temperature sintering, and the purity of the nitrogen gas is ≥99.99%.

[0010] Preferably, in step S6, the outer surface of the blank is wiped before spraying to remove impurities, and the silicon nitride coating is evenly sprayed onto the outer surface of the blank using a high-pressure spraying device with a coating thickness of 0.1-0.3mm. The outer wall is then polished using a diamond wheel and polished with 2000-5000 grit polishing compound.

[0011] The repair process for high-precision quartz crucibles includes the following steps: A1. Acquire images of defects on the outer surface of the quartz crucible, and determine the size of the defects on the outer surface of the quartz crucible based on image processing methods; A2. Pre-treat the defects, including cleaning and polishing, fill the defects with the slurry obtained during the preparation process, and shape them; A3. The repaired area is cured by heating at 1200℃ in a nitrogen atmosphere for 2 hours, and then polished. Quality is tested by appearance, size, shock resistance and high temperature resistance.

[0012] Preferably, in step A1, image acquisition is performed in real time using an industrial camera to acquire multi-angle images of the outer surface of the quartz crucible. After preprocessing the acquired images, they are analyzed to extract the contours of defects and generate a defect size report.

[0013] Preferably, in step A2, an 800-grit diamond is used to polish the area around the defect within 10 mm; in step A3, the crucible is placed in a furnace, and nitrogen gas with a purity of ≥99.99% is introduced for 30 min to purge the furnace. The temperature is then increased to 1200℃ at a rate of 5℃ / min and held for 2 h.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention utilizes ultrasonic dispersion of carbon nanotubes to form an enhanced network. Combined with the synergistic effect of manganese dioxide and co-solvent, this results in a crucible density ≥96% and an increase in flexural strength of 20-30%. The silicon nitride coating is metallurgically bonded to the substrate after high-temperature curing, enhancing protection and extending service life by more than 30%. High-precision molds and dust-free finishing effectively reduce defect rates. Material selection balances performance and cost, and the process is compatible with existing production lines, allowing for mass production without large-scale modifications. The product possesses comprehensive high-temperature resistance and thermal shock resistance, making it widely applicable to high-precision applications in semiconductors, photovoltaics, and special smelting. Attached Figure Description

[0015] Figure 1 This is a flowchart of the preparation steps of the present invention. Detailed Implementation

[0016] The following description is intended to disclose the invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art.

[0017] Reference Figure 1 As shown, the fabrication process of the high-precision quartz crucible includes the following steps: S1. Prepare materials, including: 100-700 parts of refractory clay, 20-500 parts of quartz sand, 10-300 parts of manganese dioxide, 20-450 parts of silicon nitride coating, 10-100 parts of carbon nanotubes, 10-30 parts of binder, 20-50 parts of stabilizer, 20-60 parts of co-solvent, and 10-20 parts of modifier; S2. Weigh the materials according to the proportion, mix the refractory clay, manganese dioxide and quartz sand to obtain a mixture; put the carbon nanotubes into anhydrous ethanol and perform ultrasonic dispersion treatment to obtain a carbon nanotube dispersion; mix the mixture and the carbon nanotube dispersion and stir; add binder, stabilizer, cosolvent and modifier during stirring to continuously adjust the viscosity of the slurry. S3. Select a stainless steel mold, coat the inner wall of the mold with a release agent, and use the vacuum injection method to inject the slurry into the mold to remove air bubbles in the slurry. Let it stand for 2-4 hours until the material has initially solidified, and then demold it. Place the demolded blank in a dust-free workshop to trim the outer wall. S4. Perform drying treatment: dry the embryos at room temperature with ventilation for 12 hours and then heat them at a gradient of 50-120℃. S5. Firing: Preheat the temperature to 400-600℃ for pre-firing and degreasing. After completion, heat the temperature to 1650-1750℃ under nitrogen protection for high-temperature sintering and hold for 3-5 hours. S6. Remove the blank, spray silicon nitride coating on the outer surface and fire and cure it; remove it and perform subsequent grinding and polishing to obtain a quartz crucible.

[0018] In this application, carbon nanotubes are ultrasonically dispersed to form a uniform reinforced network. Combined with manganese dioxide to promote substrate lattice fusion and a flux to optimize sintering, the crucible density is ≥96%, and the flexural strength is increased by 20-30%. Stabilizers inhibit crystal transformation and deformation. The silicon nitride coating is metallurgically bonded to the substrate after high-temperature curing, which significantly improves high-temperature resistance and corrosion resistance, and extends service life by more than 30%.

[0019] In step S1, the binder is one of water glass, alumina molten adhesive, and polyvinyl alcohol; the stabilizer is one of calcium oxide, magnesium oxide, and zirconium oxide; the co-solvent is one of borax, boric acid, and calcium fluoride; and the modifier is one of silane coupling agent, titanate coupling agent, and polyethylene glycol.

[0020] In step S2, a planetary mixer is used for mixing. The mixture is dry-mixed at 250 rpm for 40 minutes, with the wall scraped every 10 minutes to obtain a uniform mixture. The ultrasonic dispersion time is 30 minutes and the frequency is 40 kHz. The dispersion is then injected into the mixture, and the speed is adjusted to 180 rpm for 20 minutes. The viscosity is monitored in real time using a rotational viscometer, and the viscosity is adjusted by adding anhydrous ethanol or dry mixture.

[0021] In step S3, the vacuum grouting method involves injecting the grout into the mold at a rate of 5-10 mL / s and maintaining a vacuum of -0.08 MPa for 30 minutes to remove air bubbles. The mold is then left to stand in a cleanroom at 25±2℃ and 50-60% humidity for 2-4 hours for initial curing. After demolding, the outer wall flash is trimmed with a diamond scraper, and imperfections are polished.

[0022] In step S4, the trimmed blanks are placed in layers on a breathable tray with a spacing of ≥5cm; they are ventilated and dried for 12 hours, during which the blanks are turned over once every 4 hours; after completion, they are transferred to a drying oven, and a gradient heating program is started, raising the temperature from 50℃ to 80℃ at a rate of 5℃ / h and holding for 2 hours; then the temperature is raised to 120℃ at the same rate and held for 4 hours, keeping the humidity inside the oven ≤30%.

[0023] In step S5, the pre-calcination and degreasing process involves raising the temperature from room temperature to 400-600℃ at a rate of 5℃ / min, and holding it at that temperature for 2 hours. The complete decomposition of organic matter (degreasing rate ≥98%) is confirmed by monitoring the exhaust gas inside the kiln. During this period, the kiln conditions are observed in real time to prevent local overheating that could lead to deformation of the green body. After degreasing, nitrogen gas is introduced for high-temperature sintering, with a nitrogen purity of ≥99.99%.

[0024] In step S6, before spraying, wipe the outer surface of the blank to remove impurities, and use a high-pressure spraying device to spray the silicon nitride coating evenly onto the outer surface of the blank, with a coating thickness of 0.1-0.3mm; use a diamond wheel to grind the outer wall, and polish with 2000-5000 grit polishing paste.

[0025] The repair process for high-precision quartz crucibles includes the following steps: A1. Acquire images of defects on the outer surface of the quartz crucible, and determine the size of the defects on the outer surface of the quartz crucible based on image processing methods; A2. Pre-treat the defects, including cleaning and polishing, fill the defects with the slurry obtained during the preparation process, and shape them; A3. The repaired area is cured by heating at 1200℃ in a nitrogen atmosphere for 2 hours, and then polished. Quality is tested by appearance, size, shock resistance and high temperature resistance.

[0026] In step A1, image acquisition is performed in real time using an industrial camera to capture multi-angle images of the outer surface of the quartz crucible. After preprocessing the acquired images, they are analyzed to extract the contours of defects and generate a defect size report.

[0027] In step A2, use an 800-grit diamond to polish the area around the defect within 10mm; in step A3, place the crucible in the furnace, purge with nitrogen gas of ≥99.99% purity for 30 minutes, raise the temperature to 1200℃ at 5℃ / min, and hold for 2 hours.

[0028] Quality inspection includes: Appearance inspection The testing environment is a cleanroom with a constant temperature of 25±2℃ and humidity of 50-60% to avoid dust interfering with the test results. Testing equipment and methods: A 10x magnifying glass combined with a 12-megapixel industrial camera was used to scan and photograph the outer surface, mouth edge and inner wall of the crucible from all directions; the focus was on observing whether there were bubbles, cracks, coating peeling, scratches and material shortage defects, and at the same time checking whether the surface color was uniform and consistent, with no obvious color difference; Judgment criteria: If there are no defects exceeding the above threshold, and the surface has no obvious drips or burrs, and the opening has no sharp edges, the appearance is qualified. Size inspection Testing equipment: coordinate measuring machine, roundness tester, wall thickness micrometer; Testing content and methods: Key dimensions: Measure the crucible diameter and height, and calculate the deviation between the average value and the design value; Wall thickness uniformity: Use a wall thickness micrometer to measure every 20 mm along the height of the crucible, take 8 evenly distributed points in each circle, and record the maximum and minimum wall thickness difference. Roundness error: The deviation between the actual profile and the ideal circle is calculated by measuring the opening and middle sections with a roundness meter.

[0029] Judgment criteria: Dimensional error ≤ ±0.05mm, wall thickness uniformity ±0.2mm, roundness error ≤ 0.1mm, are considered to be dimensionally qualified; Thermal shock resistance testing Testing equipment: high-temperature chamber, low-temperature cooling device, impact testing machine; Testing method: A rapid cooling and heating cycle test was conducted, using three representative samples. The first step is to place the crucible in a high-temperature chamber, heat it to 1000℃, and keep it at that temperature for 1 hour; The second step is to quickly remove the crucible and place it in room temperature air at 25°C, allowing it to cool naturally to room temperature, thus completing one cycle. The third step is to repeat the cycle 3 times, and observe the crucible for cracks or damage after each cycle. The judgment criteria are: after 3 cycles, if the crucible has no cracks, no damage, and no obvious deformation, it is considered to have passed the thermal shock resistance test. High temperature resistance test Testing equipment: high-temperature sintering furnace, high-temperature strength tester; Detection method: Sample preparation: Take the finished crucible, put it into a high-temperature furnace, and purge it with nitrogen gas of ≥99.99% purity to replace the air in the furnace (oxygen content ≤0.01%). High-temperature heat preservation: Heat to 1600℃ at a rate of 10℃ / min and keep warm for 2 hours; Performance verification: After the heat preservation is completed, allow the crucible to cool naturally to room temperature and observe whether there is any deformation, cracking, or coating peeling. At the same time, test the density (drainage method) and flexural strength (high temperature strength tester) after high temperature. Judgment criteria: If there is no deformation, cracking, or coating peeling after high-temperature insulation, the high-temperature resistance performance is qualified.

[0030] Comprehensive Judgment Rules Products must meet all four testing criteria—appearance, dimensions, thermal shock resistance, and high-temperature resistance—to be considered qualified. If any single criterion fails to meet the criteria, a retest must be conducted. If the retest also fails, the entire batch is deemed unqualified, and the manufacturing process must be traced back and adjusted. Example 1

[0031] The fabrication process of high-precision quartz crucibles includes the following steps: S1. Prepare materials, including: 500 parts refractory clay, 500 parts quartz sand, 300 parts manganese dioxide, 350 parts silicon nitride coating, 100 parts carbon nanotubes, 30 parts binder, 20 parts stabilizer, 20 parts co-solvent and 10 parts modifier. S2. Weigh the materials according to the proportion, mix the refractory clay, manganese dioxide and quartz sand to obtain a mixture; put the carbon nanotubes into anhydrous ethanol and perform ultrasonic dispersion treatment to obtain a carbon nanotube dispersion; mix the mixture and the carbon nanotube dispersion and stir; add binder, stabilizer, cosolvent and modifier during stirring to continuously adjust the viscosity of the slurry. S3. Select a stainless steel mold, coat the inner wall of the mold with a release agent, and use the vacuum injection method to inject the slurry into the mold to remove air bubbles in the slurry. Let it stand for 2 hours until the material has initially solidified, and then demold it. Place the demolded blank in a clean room to trim the outer wall. S4. Perform drying treatment: dry the embryos at room temperature with ventilation for 12 hours and then heat them at a gradient of 50-120℃. S5. Firing: Preheat the temperature to 400℃ for pre-firing and degreasing. After completion, heat the temperature to 1650℃ under nitrogen protection for high-temperature sintering and hold for 3 hours. S6. Remove the blank, spray silicon nitride coating on the outer surface and fire and cure it; remove it and perform subsequent grinding and polishing to obtain a quartz crucible. Example 2

[0032] The fabrication process of high-precision quartz crucibles includes the following steps: S1. Prepare materials, including: 200 parts refractory clay, 250 parts quartz sand, 100 parts manganese dioxide, 150 parts silicon nitride coating, 90 parts carbon nanotubes, 15 parts binder, 20 parts stabilizer, 20 parts co-solvent and 15 parts modifier. S2. Weigh the materials according to the proportion, mix the refractory clay, manganese dioxide and quartz sand to obtain a mixture; put the carbon nanotubes into anhydrous ethanol and perform ultrasonic dispersion treatment to obtain a carbon nanotube dispersion; mix the mixture and the carbon nanotube dispersion and stir; add binder, stabilizer, cosolvent and modifier during stirring to continuously adjust the viscosity of the slurry. S3. Select a stainless steel mold, coat the inner wall of the mold with a release agent, and use the vacuum injection method to inject the slurry into the mold to remove air bubbles in the slurry. Let it stand for 2 hours until the material has initially solidified, and then demold it. Place the demolded blank in a clean room to trim the outer wall. S4. Perform drying treatment: dry the embryos at room temperature with ventilation for 12 hours and then heat them at a gradient of 100℃. S5. Firing: Preheat the temperature to 500℃ for pre-firing and degreasing. After completion, heat the temperature to 1655℃ under nitrogen protection for high-temperature sintering and hold for 5 hours. S6. Remove the blank, spray silicon nitride coating on the outer surface and fire and cure it; remove it and perform subsequent grinding and polishing to obtain a quartz crucible.

[0033] Comparative Example 1 The crucible preparation steps are as follows: Raw material screening involves selecting high-purity aggregates, combining them with binders such as phenolic resin and clay, and removing impurity particles to ensure uniform particle size. For ingredient mixing, accurately proportion the raw materials and binder according to the mass ratio, add an appropriate amount of dispersant, and mix using mechanical stirring or ball milling. For dry mixing, mix for 1 hour until uniform, and for wet mixing, control the moisture content to 15%. The molding process employs compression molding, slurry injection, and static pressing. The compression molding pressure is 5-10 MPa. Slurry injection molding requires control of the slurry viscosity to ensure a dense structure of the blank without bubbles or cracks. The green body is placed in a drying kiln and heated gradually to 120°C for 8 hours to remove free moisture and prevent sintering cracking. The graphite crucible was calcined in an inert atmosphere at 1800℃, and the ceramic crucible was sintered in an oxidizing atmosphere at 1200℃ for 3 hours to promote grain densification. After cooling, the edges are polished and trimmed. The dimensional accuracy and pressure resistance are checked. Once qualified, the product is packaged and shipped out.

[0034] The example uses a specific composite formula, with quartz sand, refractory clay, and manganese dioxide as base materials, combined with carbon nanotubes and silicon nitride coating functional additives, with clearly defined and highly targeted components; the comparative example uses general-purpose raw materials, high-purity aggregates + phenolic resin / clay binder, without functional additives. The examples used anhydrous ethanol for ultrasonic dispersion of carbon nanotubes to precisely adjust the slurry viscosity; the comparative examples only involved mechanical stirring and ball milling, with the wet method controlling only the water content and no specific dispersion treatment. The example uses a fixed vacuum grouting method, with molds coated with release agent and finished in a dust-free workshop, ensuring precise processing. The comparative example uses multiple methods including molding, grouting, and static pressing, without any dust-free finishing steps. The example first ventilates at room temperature for 12 hours and then gradually increases the temperature, resulting in a gentler drying process; the comparative example directly dries the material in a kiln with a gradual temperature increase, which has a shorter drying cycle but is prone to stress concentration in the billet. The example adds a pre-calcination and degreasing step, with precise temperature control and extended holding time under nitrogen protection; the comparative example does not have pre-calcination, uses both oxidizing and inert atmospheres, and has a fixed holding time. Post-processing: The example adds silicon nitride coating spraying and curing, while the comparative example only involves sanding and trimming the edges; Functional additives, ultrasonic dispersion, improve crucible strength, high temperature resistance and wear resistance; Vacuum grouting, dust-free finishing, and gentle drying reduce bubbles, cracks, and stress in the billet, ensuring high precision. Pre-firing degreasing and nitrogen-protected sintering remove impurities and residual moisture, prevent oxidation, and improve the density and stability of the green body; The customized process is adapted to the characteristics of quartz material, and the finished product has better dimensional accuracy, mechanical properties and service life than the general process products.

[0035] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention. The scope of protection claimed by the appended claims and their equivalents is defined.

Claims

1. A manufacturing process for a high-precision quartz crucible, characterized in that, The preparation steps are as follows: S1. Prepare materials, including: 100-700 parts of refractory clay, 20-500 parts of quartz sand, 10-300 parts of manganese dioxide, 20-450 parts of silicon nitride coating, 10-100 parts of carbon nanotubes, 10-30 parts of binder, 20-50 parts of stabilizer, 20-60 parts of co-solvent, and 10-20 parts of modifier; S2. Weigh the materials according to the proportion, mix the refractory clay, manganese dioxide and quartz sand to obtain a mixture; put the carbon nanotubes into anhydrous ethanol and perform ultrasonic dispersion treatment to obtain a carbon nanotube dispersion; mix the mixture and the carbon nanotube dispersion and stir; add binder, stabilizer, cosolvent and modifier during stirring to continuously adjust the viscosity of the slurry. S3. Select a stainless steel mold, coat the inner wall of the mold with a release agent, and use the vacuum injection method to inject the slurry into the mold to remove air bubbles in the slurry. Let it stand for 2-4 hours until the material has initially solidified, and then demold it. Place the demolded blank in a dust-free workshop to trim the outer wall. S4. Perform drying treatment: dry the embryos at room temperature with ventilation for 12 hours and then heat them at a gradient of 50-120℃. S5. Firing: Preheat the temperature to 400-600℃ for pre-firing and degreasing. After completion, heat the temperature to 1650-1750℃ under nitrogen protection for high-temperature sintering and hold for 3-5 hours. S6. Remove the blank, spray silicon nitride coating on the outer surface and fire and cure it; remove it and perform subsequent grinding and polishing to obtain a quartz crucible.

2. The preparation process of the high-precision quartz crucible according to claim 1, characterized in that: In step S1, the binder is one of water glass, alumina molten adhesive, and polyvinyl alcohol; the stabilizer is one of calcium oxide, magnesium oxide, and zirconium oxide; the co-solvent is one of borax, boric acid, and calcium fluoride; and the modifier is one of silane coupling agent, titanate coupling agent, and polyethylene glycol.

3. The preparation process of the high-precision quartz crucible according to claim 1, characterized in that: In step S2, a planetary mixer is used for mixing. The mixture is dry-mixed at 250 r / min for 40 min, with the wall scraped every 10 min to obtain a uniform mixture. The ultrasonic dispersion time was 30 min and the frequency was 40 kHz. The dispersion was injected into the mixture and the speed was adjusted to 180 r / min and stirred for 20 min. The viscosity was monitored in real time by a rotational viscometer and the viscosity was adjusted by adding anhydrous ethanol or dry mixture.

4. The preparation process of the high-precision quartz crucible according to claim 1, characterized in that: In step S3, the vacuum grouting method involves injecting the grout into the mold at a rate of 5-10 mL / s and maintaining a vacuum of -0.08 MPa for 30 minutes to remove air bubbles. The mold is then left to stand in a cleanroom at 25±2℃ and 50-60% humidity for 2-4 hours for initial curing. After demolding, the outer wall flash is trimmed with a diamond scraper, and imperfections are polished.

5. The preparation process of the high-precision quartz crucible according to claim 1, characterized in that: In step S4, the trimmed blanks are placed in layers on a breathable tray with a spacing of ≥5cm; they are ventilated and dried for 12 hours, during which the blanks are turned over once every 4 hours; after completion, they are transferred to a drying oven, and a gradient heating program is started, raising the temperature from 50℃ to 80℃ at a rate of 5℃ / h and holding for 2 hours; then the temperature is raised to 120℃ at the same rate and held for 4 hours, keeping the humidity inside the oven ≤30%.

6. The preparation process of the high-precision quartz crucible according to claim 1, characterized in that: In step S5, the pre-calcination and degreasing process involves raising the temperature from room temperature to 400-600℃ at a rate of 5℃ / min, and holding it at that temperature for 2 hours. The complete decomposition of organic matter (degreasing rate ≥98%) is confirmed by monitoring the exhaust gas inside the kiln. During this period, the kiln conditions are observed in real time to prevent local overheating that could lead to deformation of the green body. After degreasing, nitrogen gas is introduced for high-temperature sintering, with a nitrogen purity of ≥99.99%.

7. The preparation process of the high-precision quartz crucible according to claim 1, characterized in that: In step S6, before spraying, wipe the outer surface of the blank to remove impurities, and use a high-pressure spraying device to spray the silicon nitride coating evenly onto the outer surface of the blank, with a coating thickness of 0.1-0.3mm; use a diamond wheel to grind the outer wall, and polish with 2000-5000 grit polishing paste.

8. A repair process for high-precision quartz crucibles, characterized in that, The repair steps are as follows: A1. Acquire images of defects on the outer surface of the quartz crucible, and determine the size of the defects on the outer surface of the quartz crucible based on image processing methods; A2. Pre-treat the defects, including cleaning and polishing, fill the defects with the slurry obtained during the preparation process, and shape them; A3. Curing the repaired area by heating at 1200℃ in a nitrogen atmosphere for 2 hours, and then polishing the repaired area; Quality is tested through appearance, dimensions, shock resistance, and high-temperature resistance.

9. The repair process for the high-precision quartz crucible according to claim 8, characterized in that: In step A1, image acquisition is performed in real time using an industrial camera to capture multi-angle images of the outer surface of the quartz crucible. After preprocessing the acquired images, they are analyzed to extract the contours of defects and generate a defect size report.

10. The repair process for the high-precision quartz crucible according to claim 8, characterized in that: In step A2, use an 800-grit diamond to polish the area around the defect within 10mm; in step A3, place the crucible in the furnace, purge with nitrogen gas of ≥99.99% purity for 30 minutes, raise the temperature to 1200℃ at 5℃ / min, and hold for 2 hours.

Images