Preparation method of high-compatibility quartz crucible inner layer anti-bubble and anti-crystallization functional material layer

Abstract

This invention discloses a method for preparing a highly compatible anti-bubble and anti-crystallization functional layer for the inner layer of a quartz crucible, relating to the field of quartz crucible preparation technology. It aims to solve the problem that existing solutions cannot simultaneously address anti-bubble, anti-crystallization, compatibility, and industrialization requirements. The method includes: preparing an inhibitory layer suspension, the components of which, by mass percentage, are 92-97% fused quartz micropowder, 0.5-2% neodymium oxide micropowder, 2.1-5.5% KH550, and the balance deionized water, mixing to obtain a suspension with a viscosity of 60-90 mPa·s; applying the suspension to the inner surface of a quartz sand blank using a dual-co-directional rotary spraying process, followed by gradient heating at 40-50℃ to solidify and form a 50-100 μm thick functional layer; and then arc melting and cooling the blank to obtain the quartz crucible. This invention achieves dual functions of anti-bubble and anti-crystallization, exhibits strong compatibility with the substrate without damage, is compatible with existing production lines, has low energy consumption and cost, can significantly extend the service life of the crucible, improves the quality of monocrystalline silicon, and is suitable for industrial mass production.

Description

Technical Field

[0001] This invention patent relates to the field of quartz crucible preparation technology, specifically to a method for preparing a functional material layer for preventing bubble formation and crystallization in the inner layer of a highly compatible quartz crucible. Background Technology

[0002] The quartz crucible is the core container for the Czochralski method of growing single-crystal silicon. Its inner layer of high-purity quartz sand, formed after arc melting, is a transparent layer that directly contacts the high-temperature molten silicon. Its performance directly determines the purity of the single-crystal silicon rod and the service life of the crucible. In current processes, after the inner layer of high-purity quartz sand is laid manually by feeding and scraping, the crucible directly enters the arc melting process without any targeted treatment of the inner surface of the quartz sand blank. This leads to problems such as the expansion and rupture of microbubbles on the inner surface and high-temperature crystallization contaminating the silicon material during high-temperature melting and subsequent crystal pulling, severely affecting the service life of the crucible and the quality of the single-crystal silicon.

[0003] Existing technological solutions to address the aforementioned problems have significant shortcomings and are difficult to meet the requirements of industrial production and actual service, as detailed below:

[0004] 1. Existing patent CN108059325B, "Method for Preparing Quartz Crucibles from Composite Quartz Sand and Quartz Crucible," discloses a method for preparing quartz crucibles from composite quartz sand. This method involves separately weighing natural quartz sand and high-purity quartz sand for pre-processing and a single melting process to ultimately produce a quartz crucible. However, this method only reduces bubbles in the outer layer of the crucible and cannot solve the problem of expansion of microbubbles near the inner surface under high-temperature conditions. Furthermore, it lacks any anti-crystallization design, leading to easy crystallization on the inner surface of the crucible during the high-temperature crystal pulling stage, which in turn causes silicon contamination and affects the purity of single-crystal silicon.

[0005] 2. Existing patent CN104150755B, "A Quartz Crucible for Repeated Pulling of Single Crystal Silicon and Its Manufacturing Method," discloses that during the quartz crucible melting process, a single inert gas such as hydrogen, nitrogen, helium, or argon, or a mixture of inert gases, is introduced to replace the air remaining between quartz sand particles. Simultaneously, the inner surface of the quartz glass crucible undergoes remelting and refining treatment to remove microbubbles encased in the bubble void layer, attempting to suppress the expansion of residual microbubbles during high-temperature use. However, this solution requires an additional arc melting process, leading to an energy consumption increase of over 30%, significantly increasing production costs. Furthermore, it only reduces bubble density and cannot fundamentally suppress bubble expansion. Additionally, it lacks a protective structure to prevent internal surface rupture, making it unsuitable for long-term high-temperature service.

[0006] 3. The thermal spraying of molten silica to form a transparent layer essentially involves heating silica raw materials to a molten or semi-molten state, atomizing them with a high-pressure gas stream, and spraying them onto the inner surface of a quartz crucible blank. After cooling and solidification, a continuous transparent coating is formed, aiming to cover the blank's pores, reduce bubble exposure, and improve surface smoothness. However, this approach has significant drawbacks: high-speed spraying of molten silica impacts the inner high-purity sand, damaging its dense structure, generating microcracks or increasing porosity, which exacerbates subsequent bubble problems; furthermore, thermal spraying equipment requires high investment and energy consumption, process parameter control is difficult, and the cost-effectiveness for large-scale production is low. Additionally, it only achieves surface sealing, lacks anti-crystallization design, and cannot solve the problem of high-temperature crystallization contamination.

[0007] 4. Existing patent CN110373712A, "A Composite Crucible for Growing Crystalline Silicon and its Preparation Method," discloses a technical solution using rare earth oxides as the crucible lining. However, this solution is specifically designed for C / C shells and is not optimized for the material characteristics of quartz sand blanks. It suffers from poor substrate compatibility, easy material layer detachment, and limited functionality. It cannot simultaneously address the two core challenges of bubble expansion and high-temperature crystallization, making it difficult to adapt to existing quartz crucible production and service scenarios.

[0008] In summary, existing solutions are either functionally limited, costly, or damage the substrate, failing to simultaneously meet the dual requirements of preventing bubble expansion and crystallization, as well as being suitable for industrial mass production. Therefore, there is an urgent need for a low-cost, low-damage, multi-functional, and synergistic inner layer material processing technology that can address the performance shortcomings of existing solutions, be compatible with existing manual feeding and scraping production lines, and meet the high-performance requirements of quartz crucibles in monocrystalline silicon production. Summary of the Invention

[0009] In view of this, the purpose of this invention is to provide a method for preparing a highly compatible anti-bubble and anti-crystallization functional layer for the inner layer of a quartz crucible. The method provided by this invention achieves dual functions of anti-bubble and anti-crystallization, with strong compatibility between the layer and the substrate and no damage. It is compatible with existing production lines, has low energy consumption and cost, can significantly extend the service life of the crucible, improve the quality of monocrystalline silicon, and is suitable for industrial mass production.

[0010] The present invention discloses a method for preparing a highly compatible quartz crucible inner layer with anti-bubble and anti-crystallization functional material, which includes the following steps:

[0011] (1) Preparation of inhibitor suspension: Mix the following components evenly according to the mass percentage to prepare the inhibitor suspension; wherein, 92-97% fused silica powder, 0.5-2% neodymium oxide powder, 2.1-5.5% γ-aminopropyltriethoxysilane, and the remainder is deionized water; wherein the γ-aminopropyltriethoxysilane is of model KH-550 and manufactured by Hangzhou Jessica Chemical Co., Ltd.

[0012] Among them, fused silica micropowder serves as the base framework component of the functional layer. Its chemical composition is consistent with that of the quartz sand blank, ensuring high compatibility and structural consistency between the layer and the blank. Simultaneously, its 1-20μm particle size range effectively fills the intergranular gaps on the inner surface of the quartz sand blank, constructing a dense physical barrier layer to suppress bubble migration and expansion at high temperatures. Neodymium oxide micropowder (particle size 50-200nm) is the core functional component. On one hand, its Nd... 3+ Ionic radius and Si 4+ The material can be incorporated into the quartz lattice to form a defect compensation structure, capture alkali metal impurity ions, and suppress the crystal transformation of quartz at high temperatures, thus achieving an anti-crystallization effect. On the other hand, it can form a low-melting-point glass phase at high temperatures, with excellent fluidity, which can seal the micropores inside the material layer and further block the bubble expansion channel. γ-aminopropyltriethoxysilane (KH550) serves as a binder and interface modifier. Its molecular chain ends can react with the hydroxyl groups on the surface of inorganic powders (fused quartz micro powder, neodymium oxide micro powder) and quartz sand blanks, respectively, to form strong chemical bonds, improve the interfacial bonding force between the material layer and the blank, and prevent the material layer from falling off during high-temperature service. At the same time, it can adjust the viscosity of the suspension and improve the spray coating formability. Deionized water serves as a dispersion medium, which can uniformly disperse the solid components to form a stable suspension system, ensuring the uniformity of subsequent spray coating processes, and without introducing impurity ions, thus avoiding affecting the purity of the quartz crucible.

[0013] (2) Preparation of bubble-suppressing and anti-crystallization material layer: The bubble-suppressing material layer suspension in step (1) is sprayed onto the inner surface of the quartz sand blank, and then dry nitrogen gas at 40-50℃ is introduced and cured by gradient heating to obtain bubble-suppressing and anti-crystallization material layer with a thickness of 50-100μm.

[0014] (3) Preparation of quartz crucible: The quartz sand blank with the bubble-suppressing and anti-crystallization material layer solidified on the inner surface in step (2) is melted by electric arc method, and then the quartz crucible is obtained after cooling.

[0015] Further, in step (1), the particle size of the fused silica micro powder is 1-20 μm, and the particle size of the neodymium oxide micro powder is 50-200 nm.

[0016] Furthermore, in step (1), the specific process of uniform mixing is as follows: after adding the components together, they are first mechanically stirred, and then ultrasonically dispersed to obtain a viscosity of 60-90 mPa. The inhibited material layer suspension of s, wherein the powder agglomeration particle size is ≤50μm.

[0017] Further, in step (2), the preparation process of the quartz sand blank is as follows: in the rotating mold, the outer layer of quartz sand, the middle layer of quartz sand and the inner layer of high-purity quartz sand are laid from the outside to the inside, and the material is manually fed and scraped to obtain the quartz sand blank.

[0018] Furthermore, the inner layer of high-purity quartz sand in the quartz sand blank has a thickness of >15mm, and the surface flatness error of the quartz sand blank is ≤0.5mm.

[0019] Furthermore, in step (2), a rotary spray gun is used to spray the inner surface of the quartz sand blank. The rotary spray gun is manufactured by Alfa Laval (Shanghai) Technology Co., Ltd., and its model is Multi.

[0020] Furthermore, the rotary spray gun moves from bottom to top along the central axis of the mold at a speed of 0.1-0.3 m / s, precisely matching the coverage trajectory formed by the double rotation. This allows for adjustment of the amount of suspension adhering per unit area, preventing the material layer from being too thin and leaking due to excessive movement, or the material layer from being too thick and flowing due to excessive movement.

[0021] The minimum distance between the nozzle of the rotary spray gun and the bottom surface of the quartz sand blank is 20-30cm; this is adapted to the mist coverage range formed by the rotary spray, which can ensure that the suspension is evenly covered on the surface of the quartz sand blank, and avoid damage to the quartz sand blank caused by excessive local impact due to too close a distance.

[0022] The liquid inlet speed of the rotary spray gun is 0.5-1.0 mL / s, which matches the rotary spray gun's rotational speed of 150-250 r / min. This ensures that the suspension in the gun chamber can be fully ejected without causing pressure buildup in the chamber due to excessively fast liquid inlet or interruption of liquid ejection due to excessively slow liquid inlet.

[0023] The rotating spray gun rotates in the same direction as the mold, forming a "double co-rotation" structure. This double co-rotation design is not a single function superposition, but a synergistic efficiency mechanism based on the requirements of the spraying process. It meets the core requirements of "uniformity, stability and low damage" in industrial production. Its specific functions are as follows: First, the centrifugal force generated by the high-speed rotation of the rotating spray gun itself is the core power to achieve stable spraying of the suspension. It can quickly and evenly throw the suspension in the gun chamber outward, so that the suspension forms a fine and evenly distributed mist immediately when it is sprayed from the nozzle. This effectively avoids nozzle blockage caused by gravity retention and particle deposition of the suspension in the gun, and ensures that the flow rate of the sprayed suspension per unit time is constant, providing a basis for precise control of the subsequent material layer thickness. Secondly, the mold rotates in the same direction as the rotary spray gun, which drives the quartz sand blank to rotate synchronously. This allows the mist suspension to form a continuous spiral coverage trajectory on the inner surface of the quartz sand blank. Combined with the axial movement of the rotary spray gun, it can completely avoid the problems of local missed sprays and dead corners that exist in traditional fixed spraying, achieving 360° uniform coverage of the inner surface of the quartz sand blank. Thirdly, the bidirectional rotation in the same direction can create a speed synergy effect. The rotation of the quartz sand blank can buffer the impact force of the mist suspension sprayed onto the surface, reducing damage to the surface structure of the high-purity sand in the inner layer of the quartz sand blank. At the same time, it allows the suspension to spread quickly on the surface of the quartz sand blank, avoiding uneven material layer thickness caused by local accumulation. It takes into account both the density of the material layer and the integrity of the substrate structure, laying a good foundation for the subsequent gradient curing process.

[0024] The rotation speed of the mold is 50-90 r / min, which forms a reasonable difference with the rotation speed of the rotary spray gun. This ensures that the high rotation speed will not interfere with the stable adhesion of the suspension, and that the moderate rotation will help the suspension spread, further improving the uniformity of the material layer.

[0025] Furthermore, in step (2), the ambient temperature during the spraying process is maintained at 25-35℃ and the relative humidity is ≤40%, which can stabilize the viscosity of the suspension, avoid abnormal viscosity affecting the spinning and splashing effect, prevent the material layer from drying and cracking due to excessive moisture evaporation, reduce the mixing of air moisture into the suspension, avoid the generation of bubbles during subsequent curing, and ensure the density of the material layer.

[0026] Further, in step (2), the gradient heating method is as follows: first, maintain the temperature at 40-42℃ for 8-12 minutes; then raise the temperature to 48-50℃ and maintain it for 10-15 minutes. The core function of this gradient heating design is to adapt to the curing characteristics of the suspension layer, achieve step-by-step curing of "gentle dehydration-dense molding", and avoid cracking of the material layer or separation from the quartz sand blank. The first stage of low-temperature heat preservation at 40-42℃ can slowly remove most of the free water in the material layer at a gentle and uniform rate, preventing water from being absorbed. Rapid evaporation can create internal pores or cause shrinkage cracks in the material layer. The second stage involves heating to 48-50℃ and holding for heat. This not only completely removes residual moisture but also promotes cross-linking reactions between KH550 and fused silica powder, neodymium oxide powder, and the surface of the billet. This strengthens the bonding force between the material layer and the interface between the material layer and the silica sand billet, forming a dense and stable functional layer structure. At the same time, it avoids the mismatch in thermal expansion coefficients between the material layer and the billet caused by direct high-temperature curing, which could lead to delamination. This provides a structurally stable inner layer foundation for the subsequent arc melting process.

[0027] Further, after step (2) is completed, the mold is transported to the electric arc furnace for step (3).

[0028] Advantages of this invention:

[0029] 1. This invention discloses a method for preparing a highly compatible anti-bubble and anti-crystallization functional layer for the inner layer of a quartz crucible, achieving a synergistic dual function of anti-bubble and anti-crystallization, thus overcoming the limitation of single-function solutions in existing methods. By constructing a dense anti-bubble and anti-crystallization layer using fused quartz micropowder, and forming a dual anti-bubble mechanism through lattice doping and glass phase sealing using neodymium oxide micropowder, and simultaneously suppressing crystal transformation through the lattice defect compensation effect of neodymium oxide micropowder, compared to existing single-function solutions, this method can simultaneously block bubble expansion channels and high-temperature crystallization paths, significantly improving the overall performance of the crucible inner layer.

[0030] 2. This invention discloses a method for preparing a highly compatible anti-bubble and anti-crystallization functional layer for the inner layer of a quartz crucible. This layer possesses ultra-high substrate compatibility and low-damage characteristics, ensuring long-term stability of the anti-bubble and anti-crystallization layer. The anti-bubble and anti-crystallization layer uses fused quartz micropowder as a substrate, with a chemical composition consistent with the quartz sand blank. Combined with the interfacial cross-linking effect of KH550, a strong chemical bond is formed, preventing the layer from detaching during high-temperature service. Simultaneously, through dual-coordinated rotational spraying and precise parameter control, the spraying impact is buffered, resulting in no damage to the substrate structure and ensuring the original density of the blank.

[0031] 3. This invention discloses a method for preparing a highly compatible anti-bubble and anti-crystallization functional layer for the inner layer of a quartz crucible, offering advantages in both cost and energy efficiency, and meeting the needs of industrial mass production. The raw materials used are conventional fused silica micropowder and a small amount of neodymium oxide micropowder, combined with mature, mass-produced KH550, making them inexpensive and readily available. No additional arc melting process is required; only a low-temperature gradient curing step is added. Compared to existing inert gas-assisted melting schemes, energy consumption is reduced, and the spraying process uses mature equipment, requiring no production line modifications. Its cost-effectiveness far surpasses that of thermal spraying and other solutions.

[0032] 4. This invention discloses a method for preparing a highly compatible anti-bubble and anti-crystallization functional layer for the inner layer of a quartz crucible. The anti-bubble and anti-crystallization layer has a stable structure, significantly extending the crucible's service life and improving the quality of monocrystalline silicon. Through gradient heating and curing, a bubble-suppressing and anti-crystallization layer with a precisely controlled thickness of 50-100 μm is formed. This effectively blocks bubble migration and expansion, as well as crystallization contamination, without affecting the contact characteristics between the crucible and the silicon melt. Actual testing shows that during high-temperature crystal pulling, the bubble expansion rate is ≤3.3%, the crystallization rate is ≤0.48%, the service life is extended by more than 60%, and the purity of monocrystalline silicon is increased to over 99.99999%, meeting the requirements for high-end monocrystalline silicon production. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 OM image of the cross section of the quartz crucible prepared in Example 1 (magnification 30.4x).

[0035] Figure 2 OM image of the cross section of the quartz crucible prepared in Example 2 (magnification 30.4x).

[0036] Figure 3 OM image of the cross section of the quartz crucible prepared in Example 3 (magnification 30.4x).

[0037] Figure 4 OM image of the cross section of the quartz crucible prepared in Comparative Example 1 (without functional material layer) (magnification 30.4x).

[0038] Figure 5 OM image of the cross section of the quartz crucible prepared in Comparative Example 2 (without gradient curing) (magnification 30.4x).

[0039] Figure 6 Photograph of the inner surface of the quartz crucible prepared in Comparative Example 2 after 300 hours of service.

[0040] Figure 7 Photograph of the inner surface of the quartz crucible prepared in Example 2 after 300 hours of service. Detailed Implementation

[0041] The present invention will be further described in detail below through embodiments.

[0042] Example 1:

[0043] 1. Preparation of the inhibitor suspension: Weigh 92% fused silica micro powder (particle size 1 μm), 0.5% neodymium oxide micro powder (particle size 50 nm), 5.5% KH550, and 2% deionized water by mass percentage. After mixing the components, first mechanically stir for 30 min (300 r / min), then ultrasonically disperse for 20 min (800 W) to obtain an inhibitor suspension with a viscosity of 60 mPa·s and a powder agglomeration particle size ≤40 μm.

[0044] 2. Preparation of the bubble-suppressing and anti-crystallization layer: The quartz sand blank was prepared by manual feeding and scraping. The inner layer of high-purity quartz sand was 16mm thick, with a surface flatness error ≤0.4mm. An Alfa Laval Multi-type rotary spray gun was used, moving from bottom to top along the central axis of the mold at a speed of 0.1m / s. The minimum distance between the nozzle and the bottom surface of the blank was 20cm. The liquid inlet speed was 0.5mL / s, the rotary spraying speed was 150r / min, and the mold rotation speed was 50r / min (in the same direction as the spray gun, with dual rotation in coordination). The spraying environment temperature was 25℃, and the relative humidity was 35%. After spraying, 40℃ dry nitrogen gas was introduced, and the temperature was increased in a gradient manner for curing: 40℃ for 12min, then increased to 48℃ for 15min, forming a functional layer with a thickness of 50μm.

[0045] 3. Preparation of quartz crucibles: The solidified quartz sand blank is directly fed into an electric arc furnace along with the mold and melted using the conventional electric arc method. After cooling, quartz crucible samples are obtained.

[0046] Example 2:

[0047] 1. Preparation of the inhibitor suspension: Weigh out 94.5% fused silica micro powder (particle size 10 μm), 1.2% neodymium oxide micro powder (particle size 120 nm), 3.8% KH550, and 0.5% deionized water by mass percentage. After mixing the components, first stir mechanically for 40 min (400 r / min), then disperse ultrasonically for 25 min (1000 W) to obtain an inhibitor suspension with a viscosity of 75 mPa·s and a powder agglomeration particle size ≤45 μm.

[0048] 2. Preparation of the bubble-suppressing and anti-crystallization material layer: The inner layer of the quartz sand blank is 18mm thick with high-purity quartz sand and the surface flatness error is ≤0.3mm. The rotating spray gun moves at a speed of 0.2m / s, the minimum distance between the nozzle and the bottom surface of the blank is 25cm, the liquid inlet speed is 0.75mL / s, the rotating liquid ejection speed is 200r / min, and the mold rotation speed is 70r / min (in the same direction as the spray gun); the spraying environment temperature is 30℃ and the relative humidity is 30%. After spraying, dry nitrogen gas at 45℃ is introduced, and the temperature is gradually increased for curing: 41℃ is maintained for 10min, and then the temperature is increased to 49℃ and maintained for 12min to form a functional material layer with a thickness of 75μm.

[0049] 3. Preparation of quartz crucible: The same arc melting and cooling process as in Example 1 was used to obtain quartz crucible samples.

[0050] Example 3:

[0051] 1. Preparation of the inhibitor suspension: Weigh out 97% fused silica micro powder (particle size 20 μm), 2% neodymium oxide micro powder (particle size 200 nm), 2.1% KH550, and 1.9% deionized water by mass percentage. After mixing the components, first mechanically stir for 50 min (500 r / min), then ultrasonically disperse for 30 min (1200 W) to obtain an inhibitor suspension with a viscosity of 90 mPa·s and a powder agglomeration particle size ≤50 μm.

[0052] 2. Preparation of bubble-suppressing and anti-crystallization material layer: The inner layer of the quartz sand blank is 20mm thick with high-purity quartz sand and the surface flatness error is ≤0.5mm. The rotating spray gun moves at a speed of 0.3m / s, the minimum distance between the nozzle and the bottom surface of the blank is 30cm, the liquid inlet speed is 1.0mL / s, the rotating liquid ejection speed is 250r / min, and the mold rotation speed is 90r / min (in the same direction as the spray gun); the spraying environment temperature is 35℃ and the relative humidity is 40%. After spraying, dry nitrogen gas at 50℃ is introduced, and the temperature is gradually increased for curing: 42℃ is maintained for 8min, and then the temperature is increased to 50℃ and maintained for 10min to form a functional material layer with a thickness of 100μm.

[0053] 3. Preparation of quartz crucible: The same arc melting and cooling process as in Example 1 was used to obtain quartz crucible samples.

[0054] Comparative Example 1:

[0055] 1. Preparation of quartz sand blank: The raw materials, molds and feeding and scraping processes are completely consistent with those in Example 2. The inner layer of high-purity quartz sand is 18mm thick and the surface flatness error is ≤0.3mm.

[0056] 2. Preparation of quartz crucible: Without the spraying and curing process of the functional material layer, the quartz sand blank is directly fed into the electric arc furnace along with the mold, and the same electric arc melting parameters (current, time, cooling rate) as in Example 2 are used to obtain quartz crucible samples for verifying the core function of the functional material layer.

[0057] Comparative Example 2:

[0058] 1. Preparation of inhibition layer suspension: Using the same raw material ratio, mixing process and parameters as in Example 2, an inhibition layer suspension with a viscosity of 75 mPa·s (powder agglomeration particle size ≤ 45 μm) was prepared.

[0059] 2. Preparation of the bubble-suppressing and anti-crystallization material layer: The quartz sand blank preparation parameters, the dual-co-directional rotary spraying process (Alfa Laval Multi-type rotary spray gun, moving speed 0.2m / s, nozzle distance 25cm, liquid inlet speed 0.75mL / s, spray gun rotation speed 200r / min, mold rotation speed 70r / min), and the spraying environment (temperature 30℃, relative humidity 30%) were all exactly the same as in Example 2, forming a functional material layer with a thickness of 75μm. After spraying, gradient temperature curing was not used; instead, 50℃ dry nitrogen gas was directly introduced for constant temperature curing for 22min.

[0060] 3. Preparation of quartz crucibles: Quartz crucible samples were obtained using the same arc melting and cooling process as in Example 2, which were used to verify the effect of gradient curing process on the bonding strength of the material layer and the anti-bubble and anti-crystallization performance.

[0061] Experimental verification

[0062] For each group of quartz crucible samples from Examples 1-3 and Comparative Examples 1-2, a sample block (60mm×60mm×100mm) was cut from the same location in the central region of the crucible wall. These blocks were simultaneously placed in a 1600℃ high-temperature furnace and held for 24 hours (simulating actual single-crystal silicon crystal pulling conditions). After holding, they were allowed to cool naturally to room temperature. The sample blocks were then cut into standard cross-sectional pieces (60mm×3mm×100mm) using a wire cutter. After ultrasonic cleaning with pure water (500W, 10min) and drying at 120℃ (2h), the morphology of surface bubbles within the cross-section was observed using an optical electron microscope (OM), and the bubble expansion rate and surface crystallization rate were calculated.

[0063] Meanwhile, each set of complete crucibles was used for continuous single-crystal silicon pulling experiments. The time from the start of crystal pulling to the appearance of obvious bubble rupture, crystallization contamination, or material layer peeling that made production impossible was recorded as service life data. At the same time, the inner surface of the quartz crucible samples of Comparative Example 2 and Example 2, which reached 300 hours of service, was photographed and the material layer peeling rate was calculated. After the crystal pulling was completed, silicon rod samples were cut off and the purity of single-crystal silicon was detected by inductively coupled plasma mass spectrometry (ICP-MS, detection accuracy 0.01ppb).

[0064] Observation indicators and calculation methods: ① Bubble expansion rate: the percentage difference between the bubble volume after high temperature and the initial volume; ② Inner surface crystallization rate: the percentage of the crystallization area to the total area of ​​the observation field; ③ Single crystal silicon purity: the impurity content of the silicon rod after crystal pulling is detected by ICP-MS, and the purity value is calculated. The impurity detection range covers common harmful impurities such as Fe, Al, Ca, and Mg to ensure accurate and reliable detection results; ④ Service life: quantified by the cumulative duration of continuous crystal pulling (h), the total time for stable crystal pulling of each group of crucibles is recorded, with a target of ≥300h for samples without functional material layer and ≥500h for samples with functional material layer. The life extension ratio of coated samples relative to uncoated samples is calculated.

[0065] in Figure 1-5 OM images of Examples 1-3 and Comparative Examples 1-2, respectively, from Figure 1-3 It can be seen that the quartz crucibles prepared in Examples 1-3 have very few bubbles on the inner surface of their cross-sections, are of uniform size, show no obvious expansion, and have no visible continuous crystallization layer on the inner surface, with the crystallization areas being sporadically distributed; while Comparative Example 1 ( Figure 4 Comparative Example 2 Figure 5 In the OM image, there are a large number of bubbles with volume expansion, and a clear continuous crystallization layer is formed on the inner surface. The bubble aggregation and crystallization phenomena are significant, which directly confirms the inhibitory effect of the functional material layer and the dual co-directional rotation spraying process on bubble expansion and crystallization.

[0066] in Figure 6-7 The images show photographs of the inner surfaces of the quartz crucible samples from Comparative Example 2 and Example 2, respectively, after 300 hours of service. As can be seen from the images, after 300 hours of service, the inner surface of Comparative Example 2... Figure 6 In the photograph of the inner surface of Example 2, traces of localized material layer detachment can be clearly observed, and the boundaries of the detached area are obvious; Figure 7 In the test, the material layer was intact without any peeling or cracking, which directly proves that the gradient temperature curing process can effectively strengthen the interfacial bonding between the material layer and the blank, avoid peeling and cracking of the material layer, and significantly improve the stability of high-temperature service.

[0067] The experimental data and analysis obtained after the above observations and calculations are shown in Table 1:

[0068] Table 1 Experimental Data and Analysis

[0069]

[0070] As can be seen from the table above:

[0071] 1. Functional material layer is the core of performance: Compared with Comparative Example 1 and Examples 1-3, the bubble expansion rate and crystallization rate of the quartz crucibles prepared in Examples 1-3 are ≤3.3% and ≤0.48%, respectively, which are significantly lower than those of the quartz crucibles prepared in Comparative Example 1.

[0072] 2. Gradient curing as the core guarantee against peeling: Comparing Comparative Example 2 and Example 2, Comparative Example 2, lacking the gradient temperature curing process and only using constant temperature curing, exhibited peeling of the material layer, with significantly higher bubble expansion rate and crystallization rate than Example 2. This indicates that gradient curing, through step-by-step control of "low temperature and mild dehydration - medium temperature densification molding," can effectively avoid the problems of uneven moisture evaporation and weak interfacial bonding caused by constant temperature curing, significantly strengthening the internal cohesion of the material layer and the interfacial bonding with the preform, thus fundamentally preventing peeling and cracking during high-temperature service. Furthermore, the uniform material layer formed by dual-co-directional rotary spraying provides the structural foundation for gradient curing to fully exert its function, and the two work together to ensure the stable release of functional material layer performance.

[0073] 3. Strong process stability and practicality: The performance differences between Examples 1-3 are minimal, with bubble expansion rate and crystallization rate fluctuations ≤0.2%, no material layer peeling, and a service life ≥500h, which is 65.6%-93.8% longer than traditional processes. The purity of monocrystalline silicon reaches over 99.99999%. Combining the images and data, the process parameters of this invention are reasonable, suitable for industrial production, and fully meet the requirements of high-end monocrystalline silicon.

[0074] The above are preferred embodiments of the present invention. For those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a high-compatibility quartz crucible inner layer with anti-bubble and anti-crystallization functional material layer, characterized in that, It includes the following steps: (1) Preparation of inhibitor suspension: The following components are mixed evenly according to the mass percentage to prepare the inhibitor suspension; wherein, 92-97% fused silica powder, 0.5-2% neodymium oxide powder, 2.1-5.5% γ-aminopropyltriethoxysilane, and the remainder is deionized water; (2) Preparation of bubble-suppressing and anti-crystallization material layer: The bubble-suppressing material layer suspension in step (1) is sprayed onto the inner surface of the quartz sand blank, and then dry nitrogen gas at 40-50℃ is introduced and cured by gradient heating to obtain bubble-suppressing and anti-crystallization material layer. The thickness of the bubble-suppressing and anti-crystallization material layer is 50-100μm. The gradient heating method involves first holding the temperature at 40-42℃ for 8-12 minutes, then raising the temperature to 48-50℃ and holding it for 10-15 minutes. (3) Preparation of quartz crucible: The quartz sand blank with the bubble-suppressing and anti-crystallization material layer solidified on the inner surface in step (2) is melted by electric arc method, and then the quartz crucible is obtained after cooling.

2. The method for preparing the anti-bubble and anti-crystallization functional layer of the inner layer of the highly compatible quartz crucible according to claim 1, characterized in that, In step (1), the particle size of the fused silica micro powder is 1-20 μm, and the particle size of the neodymium oxide micro powder is 50-200 nm.

3. The method for preparing the anti-bubble and anti-crystallization functional layer of the inner layer of the highly compatible quartz crucible according to claim 1, characterized in that, In step (1), the specific process of uniform mixing is as follows: after adding the components together, they are first mechanically stirred, and then ultrasonically dispersed to obtain a viscosity of 60-90 mPa. The inhibited material layer suspension of s, wherein the powder agglomeration particle size is ≤50μm.

4. The method for preparing the anti-bubble and anti-crystallization functional layer of the inner layer of the highly compatible quartz crucible according to claim 1, characterized in that, In step (2), the preparation process of the quartz sand blank is as follows: the outer layer of quartz sand, the middle layer of quartz sand and the inner layer of high-purity quartz sand are laid in the rotating mold from the outside to the inside, and the material is manually fed and scraped to obtain the quartz sand blank.

5. The method for preparing the anti-bubble and anti-crystallization functional layer of the inner layer of the highly compatible quartz crucible according to claim 4, characterized in that, The inner layer of high-purity quartz sand in the quartz sand blank has a thickness of >15mm, and the surface flatness error of the quartz sand blank is ≤0.5mm.

6. The method for preparing the anti-bubble and anti-crystallization functional layer of the inner layer of the highly compatible quartz crucible according to claim 4, characterized in that, In step (2), a rotary spray gun is used to spray the inner surface of the quartz sand blank.

7. The method for preparing the anti-bubble and anti-crystallization functional layer of the inner layer of a highly compatible quartz crucible according to claim 6, characterized in that, The rotary spray gun moves from bottom to top along the central axis of the mold at a speed of 0.1-0.3 m / s. The minimum distance between the nozzle of the rotary spray gun and the bottom surface of the quartz sand blank is 20-30 cm. The liquid injection speed of the rotary spray gun is 0.5-1.0 mL / s, the rotation speed is 150-250 r / min, the rotary spray gun rotates in the same direction as the mold, and the rotation speed of the mold is 50-90 r / min.

8. The method for preparing the anti-bubble and anti-crystallization functional layer of the inner layer of the highly compatible quartz crucible according to claim 7, characterized in that, In step (2), the ambient temperature during the spraying process is maintained at 25-35℃ and the relative humidity is ≤40%.

9. The method for preparing the anti-bubble and anti-crystallization functional layer of the inner layer of a highly compatible quartz crucible according to claim 8, characterized in that, After step (2) is completed, the mold is transported to the electric arc furnace for step (3).

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