A high-strength quartz crucible and its preparation process

Abstract

The present invention relates to the technical field of quartz crucibles, and discloses a high-strength quartz crucible and a preparation process thereof; the high-strength quartz crucible comprises a crucible body, a coating A, a coating B and a coating C, wherein the inner surface of the crucible body is sprayed with the coating A, the coating B and the coating C in sequence from the inside to the outside; the raw materials of the coating A include 30 to 40 parts of silicon oxynitride, 30 to 40 parts of silicon dioxide, 20 to 30 parts of silicon nitride, 6 to 12 parts of silica sol, 30 to 60 parts of silica, and the like. parts of water, with a thickness of 40 to 50 μm; the raw materials of coating B include 20 to 30 parts of silicon oxynitride, 30 to 40 parts of silicon nitride, 6 to 12 parts of silicon dioxide, 6 to 12 parts of silica sol, 30 to 60 parts of water, and 4 to 8 parts of additives, with a thickness of 50 to 60 μm; the raw materials of coating C include 20 to 30 parts of silicon oxynitride, 50 to 60 parts of silicon nitride, 6 to 12 parts of silica sol, and 30 to 60 parts of water, with a thickness of 80 to 120 μm.

Description

Technical Field

[0001] The invention relates to the technical field of quartz crucibles and discloses a high-strength quartz crucible and a preparation process thereof. Background Art

[0002] Polycrystalline silicon is a crucial material for the production of photovoltaic modules. Quartz crucibles are typically used during the casting process. However, during this process, the silicon material can penetrate the crucible at high temperatures, causing it to crack and posing a serious safety hazard. Existing technologies often address this issue by spraying a silicon nitride coating on the surface of the quartz crucible. Silicon nitride is heat-resistant, chemically stable, and resistant to penetration by silicon liquid, thus protecting the crucible and ensuring smooth casting.

[0003] However, silicon nitride coatings lack strong adhesion to quartz crucibles, are prone to detachment, stick to the crucible, and exhibit low yields. While the introduction of PVA as a bonding and film-forming component can improve adhesion between the silicon nitride coating and the quartz crucible, this can lead to non-wetting between the coating and the silicon melt, causing cracking in the silicon ingot. Therefore, developing a coating with excellent adhesion to the quartz crucible body and superior performance can improve the yield and strength of quartz crucible ingots, resulting in a practical, high-strength quartz crucible. Summary of the Invention

[0004] The object of the present invention is to provide a high-strength quartz crucible and a preparation process thereof, so as to solve the problems raised in the above background technology.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] A preparation process for a high-strength quartz crucible: the high-strength quartz crucible comprises a crucible body, coating A, coating B, and coating C; coating A, coating B, and coating C are sprayed on the inner surface of the crucible body in sequence from the inside to the outside; coating A comprises silicon oxynitride, silicon dioxide, silicon nitride, silica sol, and water; coating B comprises silicon oxynitride, silicon nitride, silicon dioxide, silica sol, water, and additives; and coating C comprises silicon oxynitride, silicon nitride, silica sol, and water.

[0007] More optimally, coating A comprises the following raw materials, calculated by mass: 30-40 parts of silicon oxynitride, 30-40 parts of silicon dioxide, 20-30 parts of silicon nitride, 6-12 parts of silica sol, and 30-60 parts of water.

[0008] More optimally, coating B includes the following raw materials, calculated by mass: 20-30 parts of silicon oxynitride, 30-40 parts of silicon nitride, 6-12 parts of silicon dioxide, 6-12 parts of silica sol, 30-60 parts of water, and 4-8 parts of additives.

[0009] More optimally, coating C includes the following raw materials, calculated by mass: 20-30 parts of silicon oxynitride, 50-60 parts of silicon nitride, 6-12 parts of silica sol, and 30-60 parts of water.

[0010] More optimally, the thickness of coating A is 40-50 μm, the thickness of coating B is 50-60 μm, and the thickness of coating C is 80-120 μm.

[0011] More optimally, the preparation of the additive includes the following steps: taking terminal hydroxyl silicone oil and polyvinyl alcohol, stirring evenly, adjusting the pH to 3-5, stirring and reacting at 100°C-120°C for 4-5h, adjusting the pH to neutral, adding cyclotetrasiloxane and sulfonated cationic resin, heating to 85-95°C, reacting for 5-8h, cooling, filtering, distilling under reduced pressure, adjusting the pH to neutral, filtering, treating the filtrate with activated carbon for 3 days, filtering and taking the filtrate, adding terminal vinyl silicone oil to the filtrate, heating to 85-95°C, adding chloroplatinic acid-isopropanol solution, heating to 150-160°C and reacting for 5-6h, adding allyl alcohol polyoxyalkyl ether, methyl acrylate, methyl methacrylate, butyl acrylate, hydroxyethyl methacrylate, styrene, tert-butyl perbenzoate, dodecanol, and propylene glycol methyl ether acetate, heating to 135-145°C under a nitrogen atmosphere, and keeping warm for 4-5h to obtain the additive.

[0012] More preferably, in the chloroplatinic acid-isopropanol solution, the Pt content is 6 ppm based on the total formulation.

[0013] More optimally, the additive includes the following raw materials, in parts by mass: 35-45 parts of terminal hydroxyl silicone oil, 30-50 parts of polyvinyl alcohol, 45-55 parts of cyclotetrasiloxane, 6-8 parts of sulfonated cationic resin, 6-10 parts of terminal vinyl silicone oil, 0.05-0.15 parts of chloroplatinic acid-isopropyl alcohol solution, 10-20 parts of allyl alcohol polyoxyalkyl ether, 1-3 parts of methyl acrylate, 1-3 parts of methyl methacrylate, 5-9 parts of butyl acrylate, 1-3 parts of hydroxyethyl methacrylate, 70-80 parts of styrene, 2-5 parts of tert-butyl perbenzoate, 0.2-0.5 parts of dodecanethiol, and 50-60 parts of propylene glycol methyl ether acetate.

[0014] More optimally, the preparation of the silicon oxynitride includes the following steps: taking silicon powder and water, humidifying the silicon powder so that the mass percentage of water in the silicon powder reaches 0.5%, introducing a nitrogen and oxygen mixture, maintaining the atmosphere pressure at 2 atmospheres, heating to 1100-1300°C, keeping warm for 4-5 hours, then heating to 1200-1300°C, keeping warm for 8-12 hours, to obtain silicon oxynitride.

[0015] More optimally, the silica sol includes silicon dioxide with a particle size of 10 to 50 nm and a silicon dioxide concentration of 30 to 40 wt %; the particle size of silicon nitride is 10 to 15 μm; and the particle size of silicon powder is 1 to 5 μm.

[0016] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: (1) the inner surface of the crucible is sprayed with coatings, which are coating A, coating B and coating C from the inside to the outside; coating A includes silicon oxynitride, silicon dioxide, silicon nitride, silica sol and water, wherein silicon oxynitride accounts for the largest proportion among the three coatings, because silicon oxynitride has a stronger bonding force with silicon dioxide than silicon nitride, and adding a larger proportion of silicon oxynitride to the coating closest to the crucible is beneficial to improving the strength and density of the coating and reducing the risk of coating shedding; coating B serves as an intermediate layer, playing the role of connecting coating A and coating C, wherein an additive is added, firstly introducing polyvinyl alcohol at both ends of the end hydroxyl silicone oil, polyvinyl alcohol is a polymer containing polar groups, and has good viscosity and film-forming properties; in order to further improve the film-forming properties of coating B, cyclotetrasiloxane and sulfonated cationic resin are introduced, silicon hydrogen groups are introduced on the side chains of the end hydroxyl silicone oil, and the end vinyl silicone oil is grafted onto the side chains of the end hydroxyl silicone oil, thereby improving the spreadability and facilitating film formation; Allyl alcohol polyoxyalkyl ether, methyl acrylate, methyl methacrylate, butyl acrylate, hydroxyethyl methacrylate, styrene, tert-butyl perbenzoate, dodecyl mercaptan, and propylene glycol methyl ether acetate are used to obtain a linear random copolymer, which improves the hydrophilicity of silicone oil and can be used as a dispersant for materials such as silicon oxynitride and silicon nitride. Allyl alcohol polyoxyalkyl ether is combined with silicone oil to have excellent defoaming performance, thereby improving the problem of low coating hardness and adhesion strength caused by the presence of bubbles; coating C includes silicon oxynitride, silicon nitride, silica sol, and water, and does not introduce water-soluble film-forming and bonding components such as PVA, thereby avoiding the problem of silicon ingot cracking caused by non-wetting damage between the silicon nitride coating and the silicon melt, and due to the presence of additives in coating B, it is tightly bonded to coating B and will not fall off; in summary, the spraying order and thickness of coating A, coating B, and coating C need to be controlled according to the scheme provided by the present invention to ensure adhesion and strength. The high-strength quartz crucible prepared by this method has high yield, high strength, low pot sticking rate, and is practical.

[0017] (2) The particle size of silicon dioxide in silica sol is 10-50 nm; the particle size of silicon nitride is 10-15 μm; the particle size of silicon powder used to prepare silicon oxynitride is 1-5 μm; the combination of materials with different particle sizes can increase the density and strength of the coating. DETAILED DESCRIPTION

[0018] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0019] The following examples include the following raw materials: cyclotetrasiloxane (CAS: 2370-88-9); sulfonated cationic resin (cation exchange resin, IRC-50, Wuhan Jixin Yibang Biotechnology Co., Ltd.); chloroplatinic acid (CAS: 16941-12-1); isopropyl alcohol (CAS: 67-63-0); silicon powder (Si-01000, Zhejiang Yamei Nanotechnology Co., Ltd.); silicon dioxide (10-50 nm, Ningbo Yumu New Materials Co., Ltd.); silicon nitride (10-15 μm, Shanghai Yunfu Nanotechnology Co., Ltd.); hydroxyl-terminated silicone oil (dihydroxy-terminated, molecular weight 6.2w, Qingdao Jiulin Organic Silicon New Materials Co., Ltd.); polyvinyl alcohol (1799 type, Shanghai Haikalaman Reagent Co., Ltd.); vinyl-terminated silicone oil (model: zy-500, Jiande Zhiyou Silicon Material Co., Ltd.); allyl alcohol polyoxyalkyl ether (model: L61, Nantong Chenrun Chemical Co., Ltd.); methyl acrylate (CAS: 96-33-3); methyl methacrylate (CAS: 80-62-6); butyl acrylate (CAS: 141-32-2); hydroxyethyl methacrylate (CAS: 868-77-9); styrene (CAS: 100-42-5); tert-butyl peroxybenzoate (CAS: 614-45-9); dodecanethiol (CAS: 112-55-0); propylene glycol methyl ether acetate (CAS: 108-65-6);

[0020] The following parts are by mass;

[0021] (1) Preparation method of silicon oxynitride: silicon powder and water are taken and humidified so that the mass percentage of water in the silicon powder reaches 0.5%, and nitrogen and oxygen mixed gas is introduced, with the volume ratio of nitrogen to oxygen being 100:1. The atmosphere pressure is maintained at 2 atmospheres, and the temperature is raised to 1100-1300°C and kept at this temperature for 4-5 hours, and then raised to 1200-1300°C and kept at this temperature for 8-12 hours to obtain silicon oxynitride.

[0022] (II) Preparation Method of High-Strength Quartz Crucible: Example 1: S1: Take 35 parts of silicon oxynitride, 35 parts of silicon dioxide, 22 parts of silicon nitride, 8 parts of silica sol, and 50 parts of water, stir them evenly, spray them onto the inner surface of the crucible body, and dry them to obtain coating A. The thickness of coating A is 45 μm.

[0023] S2: Take 42 parts of hydroxyl-terminated silicone oil, add 40 parts of polyvinyl alcohol, adjust the pH to 4 with a weak acid catalyst, stir and react at 115℃ for 5 hours, adjust the pH to neutral, add 50 parts of cyclotetrasiloxane and 7 parts of sulfonated cationic resin, heat to 90℃, react for 7 hours, cool, filter, heat to 120℃, maintain -0.1MPa vacuum for 1 hour, distill under reduced pressure, adjust the pH to neutral, filter, treat the filtrate with activated carbon for 3 days, filter, add 8 parts of hydroxyl-terminated silicone oil to the filtrate. base silicone oil, heated to 90°C, added with 0.1 parts of chloroplatinic acid-isopropanol solution, heated to 155°C for reaction for 5h, added with 15 parts of allyl alcohol polyoxyalkyl ether, 2 parts of methyl acrylate, 3 parts of methyl methacrylate, 8 parts of butyl acrylate, 2 parts of hydroxyethyl methacrylate, 80 parts of styrene, 3 parts of tert-butyl perbenzoate, 0.4 parts of dodecyl mercaptan, and 55 parts of propylene glycol methyl ether acetate, heated to 140°C under a nitrogen atmosphere, and kept warm for reaction for 5h to obtain an additive;

[0024] S3: Take 25 parts of silicon oxynitride, 35 parts of silicon nitride, 10 parts of silicon dioxide, 8 parts of silica sol, 50 parts of water, and 7 parts of additives, stir evenly, spray onto the surface of coating A, and dry to obtain coating B. The thickness of coating B is 55 μm.

[0025] S4: Take 22 parts of silicon oxynitride, 55 parts of silicon nitride, 10 parts of silica sol, and 40 parts of water, stir evenly, spray them onto the surface of coating B, and dry to obtain coating C. The thickness of coating C is 100 μm; the crucible body sprayed with coating A, coating B, and coating C in sequence is a high-strength quartz crucible.

[0026] Example 2: S1: Take 40 parts of silicon oxynitride, 30 parts of silicon dioxide, 20 parts of silicon nitride, 6 parts of silica sol, and 50 parts of water, stir evenly, spray them onto the inner surface of the crucible body, and dry to obtain coating A. The thickness of coating A is 40 μm;

[0027] S2: Take 45 parts of hydroxyl-terminated silicone oil, add 50 parts of polyvinyl alcohol, adjust the pH to 4 with a weak acid catalyst, stir and react at 115°C for 5 hours, adjust the pH to neutral, add 50 parts of cyclotetrasiloxane and 7 parts of sulfonated cationic resin, heat to 90°C, react for 7 hours, cool, filter, heat to 120°C, maintain -0.1MPa vacuum for 1 hour, distill under reduced pressure, adjust the pH to neutral, filter, treat the filtrate with activated carbon for 3 days, filter, add 10 parts of hydroxyl-terminated silicone oil to the filtrate, and add 10 parts of hydroxyl-terminated silicone oil to the filtrate. Alkenyl silicone oil, heated to 90°C, added with 0.1 parts of chloroplatinic acid-isopropanol solution, heated to 155°C for reaction for 5 hours, added with 10 parts of allyl alcohol polyoxyalkyl ether, 3 parts of methyl acrylate, 3 parts of methyl methacrylate, 5 parts of butyl acrylate, 3 parts of hydroxyethyl methacrylate, 70 parts of styrene, 5 parts of tert-butyl perbenzoate, 0.5 parts of dodecyl mercaptan, and 60 parts of propylene glycol methyl ether acetate, heated to 140°C under a nitrogen atmosphere, and kept warm for reaction for 5 hours to obtain the additive;

[0028] S3: Take 20 parts of silicon oxynitride, 40 parts of silicon nitride, 12 parts of silicon dioxide, 6 parts of silica sol, 50 parts of water, and 4 parts of additives, mix them evenly, spray them onto the surface of coating A, and dry them to obtain coating B. The thickness of coating B is 50 μm.

[0029] S4: Take 22 parts of silicon oxynitride, 60 parts of silicon nitride, 6 parts of silica sol, and 40 parts of water, stir evenly, spray them onto the surface of coating B, and dry to obtain coating C. The thickness of coating C is 110 μm; the crucible body sprayed with coating A, coating B, and coating C in sequence is a high-strength quartz crucible.

[0030] Example 3: S1: Take 40 parts of silicon oxynitride, 40 parts of silicon dioxide, 20 parts of silicon nitride, 12 parts of silica sol, and 50 parts of water, stir evenly, spray them onto the inner surface of the crucible body, and dry to obtain coating A. The thickness of coating A is 50 μm.

[0031] S2: Take 45 parts of hydroxyl-terminated silicone oil, add 50 parts of polyvinyl alcohol, adjust the pH to 4 with a weak acid catalyst, stir and react at 115°C for 5 hours, adjust the pH to neutral, add 50 parts of cyclotetrasiloxane and 7 parts of sulfonated cationic resin, heat to 90°C, react for 7 hours, cool, filter, heat to 120°C, maintain -0.1MPa vacuum for 1 hour, distill under reduced pressure, adjust the pH to neutral, filter, treat the filtrate with activated carbon for 3 days, filter, add 10 parts of hydroxyl-terminated silicone oil to the filtrate, and add 10 parts of hydroxyl-terminated silicone oil to the filtrate. Alkenyl silicone oil, heated to 90°C, added with 0.1 parts of chloroplatinic acid-isopropanol solution, heated to 155°C for reaction for 5 hours, added with 10 parts of allyl alcohol polyoxyalkyl ether, 1 part of methyl acrylate, 3 parts of methyl methacrylate, 9 parts of butyl acrylate, 3 parts of hydroxyethyl methacrylate, 80 parts of styrene, 5 parts of tert-butyl perbenzoate, 0.5 parts of dodecyl mercaptan, and 60 parts of propylene glycol methyl ether acetate, heated to 140°C under a nitrogen atmosphere, and kept warm for reaction for 5 hours to obtain the additive;

[0032] S3: Take 30 parts of silicon oxynitride, 30 parts of silicon nitride, 12 parts of silicon dioxide, 6 parts of silica sol, 50 parts of water, and 8 parts of additives, mix them evenly, spray them onto the surface of coating A, and dry them to obtain coating B. The thickness of coating B is 60 μm.

[0033] S4: Take 30 parts of silicon oxynitride, 60 parts of silicon nitride, 6 parts of silica sol, and 40 parts of water, stir evenly, spray them onto the surface of coating B, and dry to obtain coating C. The thickness of coating C is 100 μm; the crucible body sprayed with coating A, coating B, and coating C in sequence is a high-strength quartz crucible.

[0034] Comparative Example 1 (no additives were introduced, and the remaining steps were the same as in Example 1): S1: 35 parts of silicon oxynitride, 35 parts of silicon dioxide, 22 parts of silicon nitride, 8 parts of silica sol, and 50 parts of water were mixed and uniformly applied to the inner surface of the crucible body, and dried to obtain a coating A having a thickness of 45 μm.

[0035] S2: Take 25 parts of silicon oxynitride, 35 parts of silicon nitride, 10 parts of silicon dioxide, 8 parts of silica sol, and 50 parts of water, mix them evenly, spray them onto the surface of coating A, and dry them to obtain coating B. The thickness of coating B is 55 μm.

[0036] S3: Take 22 parts of silicon oxynitride, 55 parts of silicon nitride, 10 parts of silica sol, and 40 parts of water, stir evenly, spray them onto the surface of coating B, and dry to obtain coating C. The thickness of coating C is 100 μm; the crucible body sprayed with coating A, coating B, and coating C in sequence is a high-strength quartz crucible.

[0037] Comparative Example 2 (additives were also introduced into coating C, and the remaining steps were consistent with Example 1): S1: 35 parts of silicon oxynitride, 35 parts of silicon dioxide, 22 parts of silicon nitride, 8 parts of silica sol, and 50 parts of water were mixed and uniformly applied to the inner surface of the crucible body, and dried to obtain coating A. The thickness of coating A was 45 μm.

[0038] S2: Take 42 parts of hydroxyl-terminated silicone oil, add 40 parts of polyvinyl alcohol, adjust the pH to 4 with a weak acid catalyst, stir and react at 115℃ for 5 hours, adjust the pH to neutral, add 50 parts of cyclotetrasiloxane and 7 parts of sulfonated cationic resin, heat to 90℃, react for 7 hours, cool, filter, heat to 120℃, maintain -0.1MPa vacuum for 1 hour, distill under reduced pressure, adjust the pH to neutral, filter, treat the filtrate with activated carbon for 3 days, filter, add 8 parts of hydroxyl-terminated silicone oil to the filtrate. base silicone oil, heated to 90°C, added with 0.1 parts of chloroplatinic acid-isopropanol solution, heated to 155°C for reaction for 5h, added with 15 parts of allyl alcohol polyoxyalkyl ether, 2 parts of methyl acrylate, 3 parts of methyl methacrylate, 8 parts of butyl acrylate, 2 parts of hydroxyethyl methacrylate, 80 parts of styrene, 3 parts of tert-butyl perbenzoate, 0.4 parts of dodecyl mercaptan, and 55 parts of propylene glycol methyl ether acetate, heated to 140°C under a nitrogen atmosphere, and kept warm for reaction for 5h to obtain an additive;

[0039] S3: Take 25 parts of silicon oxynitride, 35 parts of silicon nitride, 10 parts of silicon dioxide, 8 parts of silica sol, 50 parts of water, and 7 parts of additives, stir evenly, spray onto the surface of coating A, and dry to obtain coating B. The thickness of coating B is 55 μm.

[0040] S4: Take 22 parts of silicon oxynitride, 55 parts of silicon nitride, 10 parts of silica sol, 40 parts of water, and 7 parts of additives, stir evenly, spray them onto the surface of coating B, and dry to obtain coating C. The thickness of coating C is 100 μm; the crucible body sprayed with coating A, coating B, and coating C in sequence is a high-strength quartz crucible.

[0041] Comparative Example 3 (changing the order of coatings A, B, and C; the remaining steps are the same as in Example 1): S1: 35 parts of silicon oxynitride, 35 parts of silicon dioxide, 22 parts of silicon nitride, 8 parts of silica sol, and 50 parts of water are mixed and uniformly applied to the inner surface of the crucible body, and dried to obtain coating A. The thickness of coating A is 45 μm.

[0042] S2: Take 42 parts of hydroxyl-terminated silicone oil, add 40 parts of polyvinyl alcohol, adjust the pH to 4 with a weak acid catalyst, stir and react at 115℃ for 5 hours, adjust the pH to neutral, add 50 parts of cyclotetrasiloxane and 7 parts of sulfonated cationic resin, heat to 90℃, react for 7 hours, cool, filter, heat to 120℃, maintain -0.1MPa vacuum for 1 hour, distill under reduced pressure, adjust the pH to neutral, filter, treat the filtrate with activated carbon for 3 days, filter, add 8 parts of hydroxyl-terminated silicone oil to the filtrate. base silicone oil, heated to 90°C, added with 0.1 parts of chloroplatinic acid-isopropanol solution, heated to 155°C for reaction for 5h, added with 15 parts of allyl alcohol polyoxyalkyl ether, 2 parts of methyl acrylate, 3 parts of methyl methacrylate, 8 parts of butyl acrylate, 2 parts of hydroxyethyl methacrylate, 80 parts of styrene, 3 parts of tert-butyl perbenzoate, 0.4 parts of dodecyl mercaptan, and 55 parts of propylene glycol methyl ether acetate, heated to 140°C under a nitrogen atmosphere, and kept warm for reaction for 5h to obtain an additive;

[0043] S3: Take 25 parts of silicon oxynitride, 35 parts of silicon nitride, 10 parts of silicon dioxide, 8 parts of silica sol, 50 parts of water, and 7 parts of additives, stir evenly, spray onto the surface of coating A, and dry to obtain coating B. The thickness of coating B is 55 μm.

[0044] S4: Take 22 parts of silicon oxynitride, 55 parts of silicon nitride, 10 parts of silica sol, and 40 parts of water, stir evenly, spray them onto the surface of coating B, and dry to obtain coating C. The thickness of coating C is 100 μm; the crucible body sprayed with coating C, coating B, and coating A in sequence is a high-strength quartz crucible.

[0045] Comparative Example 4 (the thicknesses of coatings A, B, and C were changed, and the remaining steps were consistent with Example 1): S1: 35 parts of silicon oxynitride, 35 parts of silicon dioxide, 22 parts of silicon nitride, 8 parts of silica sol, and 50 parts of water were mixed and uniformly applied to the inner surface of the crucible body, and dried to obtain coating A. The thickness of coating A was 30 μm.

[0046] S2: Take 42 parts of hydroxyl-terminated silicone oil, add 40 parts of polyvinyl alcohol, adjust the pH to 4 with a weak acid catalyst, stir and react at 115℃ for 5 hours, adjust the pH to neutral, add 50 parts of cyclotetrasiloxane and 7 parts of sulfonated cationic resin, heat to 90℃, react for 7 hours, cool, filter, heat to 120℃, maintain -0.1MPa vacuum for 1 hour, distill under reduced pressure, adjust the pH to neutral, filter, treat the filtrate with activated carbon for 3 days, filter, add 8 parts of hydroxyl-terminated silicone oil to the filtrate. base silicone oil, heated to 90°C, added with 0.1 parts of chloroplatinic acid-isopropanol solution, heated to 155°C for reaction for 5h, added with 15 parts of allyl alcohol polyoxyalkyl ether, 2 parts of methyl acrylate, 3 parts of methyl methacrylate, 8 parts of butyl acrylate, 2 parts of hydroxyethyl methacrylate, 80 parts of styrene, 3 parts of tert-butyl perbenzoate, 0.4 parts of dodecyl mercaptan, and 55 parts of propylene glycol methyl ether acetate, heated to 140°C under a nitrogen atmosphere, and kept warm for reaction for 5h to obtain an additive;

[0047] S3: Take 25 parts of silicon oxynitride, 35 parts of silicon nitride, 10 parts of silicon dioxide, 8 parts of silica sol, 50 parts of water, and 7 parts of additives, mix them evenly, spray them onto the surface of coating A, and dry them to obtain coating B. The thickness of coating B is 50 μm.

[0048] S4: Take 22 parts of silicon oxynitride, 55 parts of silicon nitride, 10 parts of silica sol, and 40 parts of water, stir evenly, spray them onto the surface of coating B, and dry to obtain coating C. The thickness of coating C is 150μm; the crucible body sprayed with coating A, coating B and coating C in sequence is a high-strength quartz crucible.

[0049] Experiment: The high-strength quartz crucibles prepared in Examples 1 to 3 and Comparative Examples 1 to 4 were tested for (1) the ingot yield rate and the sticking rate; (2) the thermal shock resistance (maintaining at 1000°C for 5 minutes, quenching with water cooling, and drying, which constitutes one thermal shock, and the test was performed 100 times in total); the specific data are shown in the table below.

[0050]

[0051]

[0052] Conclusion: From Comparative Example 1, not introducing additives will lead to a decrease in the ingot yield and an increase in the pot sticking rate, which is due to the decrease in coating adhesion; in Comparative Example 2, adding additives to coating C also leads to a decrease in the ingot yield, which is because the outermost layer contains additives, so the non-wettability between the silicon nitride coating and the silicon melt is destroyed; Comparative Examples 3 and 4 prove that changing the coating spraying order and thickness will lead to reduced coating adhesion and strength, a decrease in the ingot yield, and an increase in the pot sticking rate; in summary, the present invention prepares a coating with good bonding with the quartz crucible body and good performance, which can improve the yield and strength of quartz crucible ingots, and obtain a practical high-strength quartz crucible.

[0053] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0054] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A process for preparing a high-strength quartz crucible, characterized in that: The high-strength quartz crucible comprises a crucible body, coating A, coating B, and coating C; coating A, coating B, and coating C are sprayed on the inner surface of the crucible body in sequence from the inside to the outside; coating A comprises silicon oxynitride, silicon dioxide, silicon nitride, silica sol, and water; coating B comprises silicon oxynitride, silicon nitride, silicon dioxide, silica sol, water, and additives; and raw materials of coating C are silicon oxynitride, silicon nitride, silica sol, and water; The coating B comprises the following raw materials, calculated by mass: 20-30 parts of silicon oxynitride, 30-40 parts of silicon nitride, 6-12 parts of silicon dioxide, 6-12 parts of silica sol, 30-60 parts of water, and 4-8 parts of additives; The preparation of the additive comprises the following steps: Take hydroxyl-terminated silicone oil and polyvinyl alcohol, stir evenly, adjust the pH to 3-5, stir and react at 100-120°C for 4-5h, adjust the pH to neutral, add cyclotetrasiloxane and sulfonated cationic resin, heat to 85-95°C, react for 5-8h, cool, filter, distill under reduced pressure, adjust the pH to neutral, filter, treat the filtrate with activated carbon for 3 days, filter and take the filtrate, add vinyl-terminated silicone oil to the filtrate, heat to 85-95°C, add chloroplatinic acid-isopropanol solution, heat to 150-160°C and react for 5-6h, add allyl alcohol polyoxyalkyl ether, methyl acrylate, methyl methacrylate, butyl acrylate, hydroxyethyl methacrylate, styrene, tert-butyl perbenzoate, dodecanethiol, and propylene glycol methyl ether acetate, heat to 135-145°C under a nitrogen atmosphere, and react for 4-5h to obtain the additive; The additive includes the following raw materials, calculated by mass: 35-45 parts of terminal hydroxyl silicone oil, 30-50 parts of polyvinyl alcohol, 45-55 parts of cyclotetrasiloxane, 6-8 parts of sulfonated cationic resin, 6-10 parts of terminal vinyl silicone oil, 0.05-0.15 parts of chloroplatinic acid-isopropyl alcohol solution, 10-20 parts of allyl alcohol polyoxyalkyl ether, 1-3 parts of methyl acrylate, 1-3 parts of methyl methacrylate, 5-9 parts of butyl acrylate, 1-3 parts of hydroxyethyl methacrylate, 70-80 parts of styrene, 2-5 parts of tert-butyl perbenzoate, 0.2-0.5 parts of dodecanethiol, and 50-60 parts of propylene glycol methyl ether acetate.

2. The process for preparing a high-strength quartz crucible according to claim 1, wherein: The coating A comprises the following raw materials, calculated by mass: 30-40 parts of silicon oxynitride, 30-40 parts of silicon dioxide, 20-30 parts of silicon nitride, 6-12 parts of silica sol, and 30-60 parts of water.

3. The process for preparing a high-strength quartz crucible according to claim 1, wherein: The coating C comprises the following raw materials, calculated by mass: 20-30 parts of silicon oxynitride, 50-60 parts of silicon nitride, 6-12 parts of silica sol, and 30-60 parts of water.

4. The process for preparing a high-strength quartz crucible according to claim 1, wherein: The thickness of the coating A is 40-50 μm, the thickness of the coating B is 50-60 μm, and the thickness of the coating C is 80-120 μm.

5. The process for preparing a high-strength quartz crucible according to claim 1, wherein: The preparation of the silicon oxynitride comprises the following steps: taking silicon powder and water, performing humidification treatment so that the mass percentage of water in the silicon powder reaches 0.5%, introducing a nitrogen and oxygen mixture, maintaining the atmosphere pressure at 2 atmospheres, heating to 1100-1300° C., keeping the temperature for 4-5 hours, then heating to 1200-1300° C., keeping the temperature for 8-12 hours, to obtain silicon oxynitride.

6. The process for preparing a high-strength quartz crucible according to claim 1, wherein: The silica sol comprises silicon dioxide with a particle size of 10 to 50 nm; the particle size of silicon nitride is 10 to 15 μm.

7. A high-strength quartz crucible obtained according to the preparation process of a high-strength quartz crucible according to any one of claims 1 to 6.

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