Quartz crucible with high stability and preparation method thereof

Abstract

The invention relates to the technical field of crucible preparation, in particular to a quartz crucible with high stability and a preparation method thereof.The preparation method comprises the steps that after quartz sand is subjected to acid pickling and drying, aluminum oxide and sodium carbonate are added, and arc melting and centrifugal forming are conducted to obtain a crucible base material; when it is judged that the preparation of the crucible base material does not meet the preset standard according to the structural stability evaluation value, whether the preparation of the crucible base material meets the preset standard or not is judged secondarily according to the surface curvature evaluation value of the crucible base material, or the reason that the preparation of the crucible base material does not meet the preset standard is determined according to the crystallization characteristic value; the inner wall, meeting the preset standard, of the crucible base material is cleaned, a coating material is sprayed to the inner wall of the crucible base material, and a target crucible is obtained; and when it is judged that the preparation of the target crucible does not meet the preset standard according to the quality characterization value of the coating, the spraying pressure is increased, and the preparation efficiency of the quartz crucible is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of crucible preparation, and particularly to a quartz crucible with high stability and a preparation method thereof. Background Art

[0002] A quartz crucible is a high-performance material used for high-temperature melting and refining of crystalline silicon, and is widely used in the solar energy and semiconductor fields. Its main characteristics include properties such as cleanliness, homogeneity, and high temperature resistance. The deformation point is about 1100°C, the softening point is 1730°C, the maximum continuous use temperature is 1100°C, and it can reach 1450°C in a short time.

[0003] The preparation of quartz crucibles mainly uses the arc method. The principle is to load high-purity quartz powder into a rotatable forming mold with a tilt angle, form it using centrifugal force, and then form molten quartz in the shape of a crucible through arc melting, and take it out after cooling to complete the preparation of the crucible.

[0004] Chinese Patent Application Publication No.: CN116730596A, discloses a quartz crucible and a preparation method thereof. The bulk density of the quartz crucible provided in this application is ≥1.72 g / cm 3 , the apparent porosity is ≤13.9%, and the compressive strength is ≥52 MPa. The above quartz crucible is obtained through a firing process in an inert atmosphere: the firing process includes the following steps: first arc melting, second arc melting, and stable firing. The quartz crucible obtained by using the above preparation method has a lower apparent porosity, a higher bulk density, and excellent compressive strength performance of the quartz crucible.

[0005] It can be seen that in the above technical solution, the influence of the thickness of each layer and the bubble density on the structural stability of the crucible is not considered, the influence of the centrifugation time and the melting temperature on the preparation efficiency of the crucible is not considered, and the influence of the coating porosity and the thermal conductivity gradient on the coating bonding performance is not considered, which is likely to cause thermal stress concentration or interfacial peeling of the coating, resulting in the problem of low preparation efficiency of the quartz crucible. Summary of the Invention

[0006] Therefore, the present invention provides a quartz crucible with high stability and a preparation method thereof to overcome the problems in the prior art that the influence of the thickness of each layer and the bubble density on the structural stability of the crucible is not considered, the influence of the centrifugation time and the melting temperature on the preparation efficiency of the crucible is not considered, the influence of the coating porosity and the thermal conductivity gradient on the coating bonding performance is not considered, which is likely to cause thermal stress concentration or interfacial peeling of the coating, resulting in the problem of low preparation efficiency of the quartz crucible.

[0007] To achieve the above object, on the one hand, the present invention provides a preparation method of a quartz crucible with high stability, including: After pickling and drying the quartz sand, alumina and sodium carbonate are added, and arc melting and centrifugal forming are carried out to obtain a crucible substrate. The crucible substrate is divided into an outer layer and an inner layer from the outer wall to the inner wall; Obtain the thicknesses of the inner and outer layers of the crucible substrate and the bubble density of the outer layer, and calculate the structural stability evaluation value of the crucible substrate; According to the structural stability evaluation value, if the structural stability evaluation value is greater than or equal to the first preset structural stability threshold, it is determined that the preparation of the crucible substrate does not meet the preset standard. Then, according to the magnitude relationship between the structural stability evaluation value and the second preset structural stability threshold, it is determined whether to re-determine whether the preparation of the crucible substrate meets the preset standard according to the surface curvature evaluation value, or to determine the reason why the preparation of the crucible substrate does not meet the preset standard according to the crystallization characteristic value; If it is determined that the structural stability evaluation value is less than the first preset structural stability threshold, it is determined that the preparation of the crucible substrate meets the preset standard. Clean the inner wall of the crucible substrate that meets the preset standard, spray silicon nitride on the inner wall of the crucible substrate to obtain a target crucible, and obtain the porosity of the coating of the target crucible and the thermal conductivity gradient of the coating to calculate the coating quality characterization value; If it is determined that the preparation of the target crucible does not meet the preset standard according to the coating quality characterization value and the first preset coating quality characterization value, then determine whether to increase the spraying pressure or the spraying distance according to the magnitude relationship between the coating quality characterization value and the second preset coating quality characterization value.

[0008] Further, the process of obtaining the structural stability evaluation value of the crucible substrate includes: Use a laser profiler to measure the outer layer thickness and the inner layer thickness, and calculate the natural logarithm term of the thickness ratio; Use a microscope to detect the bubble density of the outer layer, and calculate the ratio of it to the preset bubble density, denoted as the bubble density deviation ratio; Multiply the natural logarithm term of the thickness ratio by the first weight to obtain the first evaluation value; Multiply the bubble density deviation ratio by the second weight to obtain the second evaluation value; Add the first evaluation value and the second evaluation value to obtain the structural stability evaluation value of the crucible substrate.

[0009] Further, if it is determined that the structural stability evaluation value is greater than or equal to the first preset structural stability threshold, it is determined that the preparation of the crucible substrate does not meet the preset standard. Then, according to the magnitude relationship between the structural stability evaluation value and the second preset structural stability threshold, it is determined whether to re-determine whether the preparation of the crucible substrate meets the preset standard according to the surface curvature evaluation value, or to determine the reason why the preparation of the crucible substrate does not meet the preset standard according to the crystallization characteristic value, including: If it is determined that the structural stability evaluation value is greater than or equal to the first preset structural stability threshold and less than the second preset structural stability threshold, obtain the surface geometry of the crucible substrate to obtain the surface curvature evaluation value, and secondarily determine whether the preparation of the crucible substrate meets the preset standard according to the surface curvature evaluation value; If it is determined that the structural stability evaluation value is greater than or equal to the second preset structural stability threshold, obtain the crystallization area of the crucible substrate to obtain the crystallization characteristic value, and determine the reason why the preparation of the crucible substrate does not meet the preset standard according to the crystallization characteristic value.

[0010] Further, when it is secondarily determined that the preparation of the crucible substrate does not meet the preset standard according to the surface curvature evaluation value, increase the centrifugal speed according to the difference between the surface curvature evaluation value and the preset surface curvature evaluation value.

[0011] Further, the surface curvature evaluation value is the ratio of the minimum curvature to the maximum curvature of the surface geometry of the crucible substrate.

[0012] Further, there are several speed adjustment methods for increasing the centrifugal speed, and each speed adjustment method has a different increase range for the centrifugal speed.

[0013] Further, the reasons for determining that the preparation of the crucible substrate does not meet the preset standard according to the crystallization characteristic value include: If the crystallization characteristic value is less than the preset crystallization characteristic value, determine that the reason for the non - compliance of the crucible substrate preparation with the preset standard is that the centrifugation duration is too short; If the crystallization characteristic value is greater than or equal to the preset crystallization characteristic value, determine that the reason for the non - compliance of the crucible substrate preparation with the preset standard is that the arc melting temperature is too high; The crystallization characteristic value is the ratio of the crystallization area of the crucible substrate to the total surface area of the crucible substrate.

[0014] Further, if it is determined that the preparation of the target crucible does not meet the preset standard according to the coating quality characterization value and the first preset coating quality characterization value, then determine whether to increase the spraying pressure or the spraying distance according to the magnitude relationship between the coating quality characterization value and the second preset coating quality characterization value, including: Compare the coating quality characterization value with the first preset coating quality characterization value. If the coating quality characterization value is greater than or equal to the first preset coating quality characterization value, determine that the preparation of the target crucible does not meet the preset standard; If the coating quality characterization value is greater than or equal to the first preset coating quality characterization value and less than the second preset coating quality characterization value, increase the spraying pressure according to the difference between the coating quality characterization value and the first preset coating quality characterization value; If the coating quality characterization value is greater than or equal to the second preset coating quality characterization value, the spraying distance is increased according to the difference between the coating quality characterization value and the second preset coating quality characterization value.

[0015] Further, the process of obtaining the coating quality characterization value includes: Obtain a cross-sectional image of the coating using a scanning electron microscope, and statistically calculate the proportion of the pore area through image software to obtain the porosity; Use a thermal conductivity tester to measure along the thickness direction of the coating at preset layer thickness intervals to obtain the thermal conductivity gradient; Multiply the porosity by the porosity weight to obtain the first coating evaluation value; Multiply the thermal conductivity gradient by the thermal conductivity gradient weight to obtain the second coating evaluation value; Add the first coating evaluation value and the second coating evaluation value to obtain the coating quality characterization value.

[0016] On the other hand, the present invention also provides a quartz crucible prepared by a preparation method, including: a quartz crucible divided into an outer layer and an inner layer from the outer wall to the inner wall, the thickness ratio of the outer layer to the inner layer being 1:1.5 - 3.0; the area of the crystallization region of the quartz crucible accounting for less than 3% of the total inner surface area; the quartz crucible including 10 parts by weight of quartz sand, 1.5 parts by weight of alumina, and 0.5 parts by weight of sodium carbonate according to weight; The inner wall of the quartz crucible is also coated with a silicon nitride coating, the porosity of the coating being less than 5%, and the silicon nitride coating including silicon nitride and silicon dioxide, the mass ratio of silicon nitride to silicon dioxide being 50 - 70:4 - 20.

[0017] Compared with the prior art, the beneficial effects of the present invention are that the present invention uses the structural stability evaluation value to test the preparation effect of the crucible substrate, ensures the uniformity and density of the layered structure, and establishes a multi-level determination mechanism for the structural stability evaluation value, the surface curvature evaluation value, and the crystallization characteristic value; introduces a secondary determination mechanism for the surface curvature evaluation value to avoid misjudgment caused by fluctuations in a single index; and further locates the reasons for non-compliance through the crystallization characteristic value, accurately locating specific process link abnormalities such as arc melting temperature or centrifugation duration, thereby improving the preparation efficiency of the quartz crucible.

[0018] Further, the present invention constructs a structural stability evaluation value through the logarithmic ratio of the thicknesses of the inner and outer layers of the crucible substrate and the bubble density of the outer layer. By introducing the logarithmic ratio of the inner and outer layer thicknesses, the uniformity of the interlayer thickness distribution is accurately quantified, and a composite evaluation function is constructed by combining the outer layer bubble density with the thickness logarithmic ratio, thereby realizing a multi-dimensional and refined evaluation of the crucible structure stability.

[0019] Furthermore, when the structural stability evaluation value of the present invention significantly exceeds the standard, the process anomaly type is determined by correlating the crystallization characteristic value. A low crystallization area ratio indicates that the crystallization phenomenon of the crucible base material has a small impact on the overall stability, and insufficient centrifugation time results in insufficient uniform distribution of fused quartz. While an excessively high crystallization area ratio reflects that too high melting temperature causes local crystallization, thus realizing rapid positioning of process problems.

[0020] Furthermore, the present invention is provided with several speed adjustment methods for increasing the centrifugal speed, and each speed adjustment method has a different increase amplitude for the centrifugal speed, thereby realizing precise control of the increase amplitude of the centrifugal speed.

[0021] Furthermore, the present invention constructs a coating quality characterization value through the coating porosity and the thermal conductivity gradient of the coating. The porosity directly reflects the density of internal defects in the coating, affecting the mechanical strength and anti-permeability of the coating; the thermal conductivity gradient characterizes the distribution difference of heat transfer in the coating, reflecting the interface bonding state, thereby realizing multi-dimensional precise evaluation of the coating quality.

[0022] Furthermore, the present invention constructs a dynamic evaluation model for coating quality based on porosity and thermal conductivity gradient. Through the linkage adjustment mechanism of spraying pressure and spraying distance, the microstructure of the silicon nitride coating is optimized to ensure that the coating forms a continuous and dense protective layer, maintaining excellent thermal conduction efficiency while improving the corrosion resistance, thereby effectively suppressing the peeling phenomenon of the coating in a high-temperature environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a flowchart of the preparation method of the quartz crucible with high stability in the embodiment of the present invention; Figure 2 is a flowchart of determining whether the preparation of the crucible base material meets the preset standard according to the structural stability evaluation value in the embodiment of the present invention; Figure 3 is a flowchart of re-determining whether the preparation of the crucible base material meets the preset standard according to the surface curvature evaluation value in the embodiment of the present invention; Figure 4 is a flowchart of determining whether the preparation of the target crucible meets the preset standard in the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0024] In order to make the purpose and advantages of the present invention clearer, the present invention will be further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0025] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present invention and do not limit the protection scope of the present invention.

[0026] It should be noted that the data in this embodiment are obtained through comprehensive analysis and evaluation of the historical detection data and corresponding historical detection results of the present invention in the three months before this detection. Those skilled in the art can understand that the determination method of the present invention for a single above-mentioned parameter can be to select the value with the highest proportion according to the data distribution as the preset standard parameter, use weighted summation to obtain the value as the preset standard parameter, substitute each historical data into a specific formula and use the value obtained by this formula as the preset standard parameter, or other selection methods, as long as it meets the requirement that the method of the present invention can clearly define different specific situations in the single-item determination process through the obtained value.

[0027] Please refer to Figure 1 、 Figure 2 、 Figure 3 and Figure 4 as shown, which are respectively the flowchart of the preparation method of the quartz crucible with high stability in the embodiment of the present invention; the flowchart of determining whether the preparation of the crucible substrate meets the preset standard according to the structural stability evaluation value in the embodiment of the present invention; the flowchart of secondary determination of whether the preparation of the crucible substrate meets the preset standard according to the surface curvature evaluation value in the embodiment of the present invention; the flowchart of determining whether the preparation of the target crucible meets the preset standard in the embodiment of the present invention.

[0028] Please refer to Figure 1 as shown. On the one hand, the embodiment of the present invention provides a preparation method of a quartz crucible with high stability, including: Step S1, after pickling and drying quartz sand, adding alumina and sodium carbonate, and performing arc melting and centrifugal forming to obtain a crucible substrate, wherein the crucible substrate is divided into an outer layer and an inner layer from the outer wall to the inner wall; Step S2, obtaining the thicknesses of the inner and outer layers of the crucible substrate and the bubble density of the outer layer, and calculating the structural stability evaluation value of the crucible substrate; Step S3, judging according to the structural stability evaluation value that if the structural stability evaluation value is greater than or equal to the first preset structural stability threshold, it is determined that the preparation of the crucible substrate does not meet the preset standard, and then according to the magnitude relationship between the structural stability evaluation value and the second preset structural stability threshold, determining whether to perform secondary determination on whether the preparation of the crucible substrate meets the preset standard according to the surface curvature evaluation value, or determining the reason why the preparation of the crucible substrate does not meet the preset standard according to the devitrification characteristic value; Step S4, if it is determined that the structural stability evaluation value is less than the first preset structural stability threshold, it is determined that the preparation of the crucible substrate meets the preset standard. The inner wall of the crucible substrate that meets the preset standard is cleaned, and silicon nitride is sprayed on the inner wall of the crucible substrate to obtain a target crucible. The porosity of the coating of the target crucible and the thermal conductivity gradient of the coating are obtained to obtain a coating quality characterization value; Step S5, if it is determined that the preparation of the target crucible does not meet the preset standard according to the coating quality characterization value and the first preset coating quality characterization value, then according to the size relationship between the coating quality characterization value and the second preset coating quality characterization value, it is determined whether to increase the spraying pressure or the spraying distance.

[0029] In this embodiment, after pickling quartz sand with a mixed acid (HF:HNO3:H2O = 1:3:6) for 2 hours and drying at 120°C for 12 hours, 10 kg of quartz sand, 1.5 kg of alumina, and 0.5 kg of sodium carbonate are mixed, and then arc melting and centrifugation operations are carried out. The melting temperature is 2000°C, melting is carried out for 30 minutes under argon protection, the centrifugation parameters are a rotation speed of 400 rpm and a duration of 6 minutes, and the mold is preheated to 800°C to form a crucible substrate with an inner and outer layer structure.

[0030] In this embodiment, there are no bubbles in the inner layer of the crucible substrate; the purity of the quartz sand in the outer layer is lower than that of the inner layer quartz sand, and the bubble content is high.

[0031] In this embodiment, 60 wt% silicon nitride powder and 10 wt% silica are mixed, and then 30 wt% silica sol is added to form a spraying slurry. After cleaning the inner wall of the crucible substrate that meets the preset standard, spraying is carried out at a spraying pressure of 0.4 MPa and a spraying distance of 130 mm.

[0032] Specifically, it is determined whether the preparation of the crucible substrate meets the preset standard according to the structural stability evaluation value, where if the structural stability evaluation value is less than the first preset structural stability threshold of 0.32, it is determined that the preparation of the crucible substrate meets the preset standard, and the inner wall of the crucible substrate that meets the preset standard is cleaned; if the structural stability evaluation value is greater than or equal to the first preset structural stability threshold and less than the second preset structural stability threshold of 0.55, it is determined that the preparation of the crucible substrate does not meet the preset standard, and it is determined again whether the preparation of the crucible substrate meets the preset standard according to the surface curvature evaluation value; if the structural stability evaluation value is greater than or equal to the second preset structural stability threshold, it is determined that the preparation of the crucible substrate does not meet the preset standard, and the reason why the preparation of the crucible substrate does not meet the preset standard is determined according to the devitrification characteristic value.

[0033] Specifically, by comparing the structural stability evaluation value with the first preset structural stability threshold and the second preset structural stability threshold respectively, the purpose is to make the prepared crucible substrate meet the requirements that the inner and outer layer structures are uniform and the stability reaches the best state.

[0034] Specifically, the value range of the first preset structural stability threshold is (0.20, 0.45), and the value range of the second preset structural stability threshold is (0.50, 0.65). Preferably, the first preset structural stability threshold is selected as 0.32, and the second preset structural stability threshold is selected as 0.55.

[0035] Specifically, the structural stability evaluation value of the crucible substrate is calculated by the following formula:

[0036] In the formula, S represents the structural stability evaluation value; α represents the first weight, and α is set to 0.57; h1 represents the outer layer thickness; h2 represents the inner layer thickness; β represents the second weight, and β is set to 0.43; represents the bubble density of the outer layer; represents the preset bubble density, and is set = 10 pieces / cm 3 .

[0037] Specifically, according to the surface curvature evaluation value, it is determined whether the preparation of the crucible substrate meets the preset standard. Among them, If the surface curvature evaluation value is less than the preset surface curvature evaluation value of 0.28, it is determined that the preparation of the crucible substrate meets the preset standard, and the inner wall of the crucible substrate that meets the preset standard is cleaned; If the surface curvature evaluation value is greater than or equal to the preset surface curvature evaluation value, it is determined that the preparation of the crucible substrate does not meet the preset standard, and the centrifugal speed is increased according to the difference between the surface curvature evaluation value and the preset surface curvature evaluation value.

[0038] When the surface curvature evaluation value is small, it indicates that the overall shape of the substrate surface is relatively uniform and meets the preset standard; when the surface curvature evaluation value is large, the surface non-uniformity is obvious and bulges appear on the surface. At this time, the centrifugal speed is increased to improve the surface uniformity of the substrate.

[0039] Specifically, the surface curvature evaluation value is the ratio of the minimum curvature to the maximum curvature of the surface geometry of the crucible substrate.

[0040] Specifically, the increase amplitude of the centrifugal speed is positively correlated with the difference between the surface curvature evaluation value and the preset surface curvature evaluation value. In this embodiment, a three-dimensional scanner is used to obtain a number of three-dimensional points on the surface of the quartz crucible, a triangular meshing algorithm is used to reconstruct the crucible surface model, and based on local quadratic surface fitting, the maximum curvature and the minimum curvature are extracted.

[0041] In this embodiment, the historical data of products prepared in multiple batches are statistically analyzed, and the surface curvature evaluation values within the range where there are no obvious defects during subsequent coating treatment and use of the crucible are averaged to obtain a preset surface curvature evaluation value.

[0042] Specifically, several rotation speed adjustment methods are set for the increase of the centrifugal rotation speed. Among them, if the surface curvature difference is less than the first preset surface curvature difference of 0.12, the centrifugal rotation speed is increased to the corresponding value by using the first rotation speed adjustment coefficient of 1.02; if the surface curvature difference is greater than or equal to the first preset surface curvature difference and less than the second preset surface curvature difference of 0.31, the centrifugal rotation speed is increased to the corresponding value by using the second rotation speed adjustment coefficient of 1.04; if the surface curvature difference is greater than or equal to the second preset surface curvature difference, the centrifugal rotation speed is increased to the corresponding value by using the third rotation speed adjustment coefficient of 1.06; The surface curvature difference is the difference between the surface curvature evaluation value and the preset surface curvature evaluation value.

[0043] Specifically, the reasons for the non - compliance of the preparation of the crucible substrate with the preset standard are determined according to the crystallization characteristic value. Among them, if the crystallization characteristic value is less than the preset crystallization characteristic value of 0.05, it is determined that the reason for the non - compliance of the preparation of the crucible substrate with the preset standard is that the centrifugation duration is too short; if the crystallization characteristic value is greater than or equal to the preset crystallization characteristic value, it is determined that the reason for the non - compliance of the preparation of the crucible substrate with the preset standard is that the arc melting temperature is too high; The crystallization characteristic value is the ratio of the crystallization area of the crucible substrate to the total surface area of the crucible substrate. Among them, the crystallization area is obtained by scanning with a scanning electron microscope and combined with image processing software such as ImageJ software, and the total surface area is obtained by acquiring a three - dimensional model with a three - dimensional scanner and combined with three - dimensional analysis software.

[0044] In this embodiment, the value of the preset crystallization characteristic value is 0.05. The preset crystallization characteristic value is obtained by averaging the preset crystallization characteristic values within a reasonable range when the quartz crucible is in use. However, the above value is not limited to this, and those skilled in the art can also adjust this value according to actual needs.

[0045] Specifically, it is determined whether the preparation of the target crucible meets the preset standard according to the coating quality characterization value. Among them, if the coating quality characterization value is less than the first preset coating quality characterization value of 1.44, it is determined that the preparation of the target crucible meets the preset standard; If the coating quality characterization value is greater than or equal to the first preset coating quality characterization value and less than the second preset coating quality characterization value of 2.73, it is determined that the preparation of the target crucible does not meet the preset standard, and the spraying pressure is increased according to the difference between the coating quality characterization value and the first preset coating quality characterization value; If the coating quality characterization value is greater than or equal to the second preset coating quality characterization value, it is determined that the preparation of the target crucible does not meet the preset standard, and the spraying distance is increased according to the difference between the coating quality characterization value and the second preset coating quality characterization value.

[0046] Specifically, the coating quality characterization value is calculated by the following formula:

[0047] In the formula, Q represents the coating quality characterization value; λ represents the porosity weight, and λ is set to 0.6; P represents the porosity; η represents the thermal conductivity gradient weight, and η is set to 0.4; represents the thermal conductivity gradient of the coating.

[0048] In this embodiment, the porosity is obtained by scanning electron microscope image analysis, and the thermal conductivity gradient of the coating is obtained by measuring the thermal conductivity along the thickness direction of the coating with a thermal conductivity tester.

[0049] Specifically, the increase amplitude of the spraying pressure is positively correlated with the difference between the coating quality characterization value and the first preset coating quality characterization value.

[0050] In this embodiment, the value range of the first preset coating quality characterization value is (1.10, 2.00), and the value range of the second preset coating quality characterization value is (2.10, 3.00). Preferably, the first preset coating quality characterization value is 1.44, and the first preset coating quality characterization value is 2.73.

[0051] On the other hand, the present invention provides a quartz crucible prepared by the above preparation method, including: a quartz crucible divided into an outer layer and an inner layer from the outer wall to the inner wall, the thickness ratio of the outer layer to the inner layer is 1:1.5 - 3.0; the area of the devitrification region of the quartz crucible accounts for less than 3% of the total inner wall surface area; the quartz crucible includes 10 parts by weight of quartz sand, 1.5 parts by weight of alumina, and 0.5 parts by weight of sodium carbonate according to parts by weight; The inner wall of the quartz crucible is also coated with a silicon nitride coating, the porosity of the coating is less than 5%, the silicon nitride coating includes silicon nitride and silicon dioxide, and the mass ratio of silicon nitride to silicon dioxide is 50 - 70:4 - 20.

[0052] So far, the technical solution of the present invention has been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, those skilled in the art can easily understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

[0053] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A preparation method of a quartz crucible with high stability, characterized in that, Including: After pickling and drying quartz sand, add alumina and sodium carbonate, and carry out arc melting and centrifugal forming to obtain a crucible substrate. The crucible substrate is divided into an outer layer and an inner layer from the outer wall to the inner wall; Obtain the thicknesses of the inner and outer layers of the crucible substrate and the bubble density of the outer layer, and calculate the structural stability evaluation value of the crucible substrate; According to the structural stability evaluation value, if the structural stability evaluation value is greater than or equal to the first preset structural stability threshold, it is determined that the preparation of the crucible substrate does not meet the preset standard. Then, according to the magnitude relationship between the structural stability evaluation value and the second preset structural stability threshold, it is determined whether to re-determine whether the preparation of the crucible substrate meets the preset standard according to the surface curvature evaluation value, or determine the reason why the preparation of the crucible substrate does not meet the preset standard according to the crystallization characteristic value; If it is determined that the structural stability evaluation value is less than the first preset structural stability threshold, it is determined that the preparation of the crucible substrate meets the preset standard. Clean the inner wall of the crucible substrate that meets the preset standard, spray silicon nitride on the inner wall of the crucible substrate to obtain a target crucible, and obtain the porosity of the coating of the target crucible and the thermal conductivity gradient of the coating to calculate the coating quality characterization value; If it is determined that the preparation of the target crucible does not meet the preset standard according to the coating quality characterization value and the first preset coating quality characterization value, then determine whether to increase the spraying pressure or the spraying distance according to the magnitude relationship between the coating quality characterization value and the second preset coating quality characterization value.

2. The preparation method of the quartz crucible with high stability according to claim 1, wherein, The process for obtaining the structural stability evaluation value of the crucible substrate includes: Use a laser profiler to measure the outer layer thickness and the inner layer thickness, and calculate the natural logarithm term of the thickness ratio; Use a microscope to detect and obtain the bubble density of the outer layer, and calculate the ratio of it to the preset bubble density, denoted as the bubble density deviation ratio; Multiply the natural logarithm term of the thickness ratio by the first weight to obtain the first evaluation value; Multiply the bubble density deviation ratio by the second weight to obtain the second evaluation value; Add the first evaluation value and the second evaluation value to obtain the structural stability evaluation value of the crucible substrate.

3. The preparation method of the quartz crucible with high stability according to claim 2, characterized in that, If it is determined that the structural stability evaluation value is greater than or equal to the first preset structural stability threshold, it is determined that the preparation of the crucible substrate does not meet the preset standard. Then, according to the magnitude relationship between the structural stability evaluation value and the second preset structural stability threshold, it is determined whether to re-determine whether the preparation of the crucible substrate meets the preset standard according to the surface curvature evaluation value, or determine the reason why the preparation of the crucible substrate does not meet the preset standard according to the crystallization characteristic value, including: If it is determined that the structural stability evaluation value is greater than or equal to the first preset structural stability threshold and less than the second preset structural stability threshold, obtain the surface geometry of the crucible substrate to obtain the surface curvature evaluation value, and re-determine whether the preparation of the crucible substrate meets the preset standard according to the surface curvature evaluation value; If it is determined that the structural stability evaluation value is greater than or equal to the second preset structural stability threshold, obtain the crystallization area of the crucible substrate to obtain the crystallization characteristic value, and determine the reason why the preparation of the crucible substrate does not meet the preset standard according to the crystallization characteristic value.

4. The preparation method of the quartz crucible with high stability according to claim 2, wherein, When it is re-determined that the preparation of the crucible substrate does not meet the preset standard according to the surface curvature evaluation value, increase the centrifugal speed according to the difference between the surface curvature evaluation value and the preset surface curvature evaluation value.

5. The preparation method of the quartz crucible with high stability according to claim 4, characterized in that, The surface curvature evaluation value is the ratio of the minimum curvature to the maximum curvature of the surface geometry of the crucible substrate.

6. The preparation method of the quartz crucible with high stability according to claim 5, characterized in that, There are several rotational speed adjustment methods for increasing the centrifugal rotational speed, and each rotational speed adjustment method has a different increase amplitude for the centrifugal rotational speed.

7. The preparation method of the quartz crucible with high stability according to claim 6, characterized in that, The reasons for determining that the preparation of the crucible substrate does not meet the preset standard according to the crystallization characteristic value include: If the crystallization characteristic value is less than the preset crystallization characteristic value, it is determined that the reason for the preparation of the crucible substrate not meeting the preset standard is that the centrifugation duration is too short; If the crystallization characteristic value is greater than or equal to the preset crystallization characteristic value, it is determined that the reason for the preparation of the crucible substrate not meeting the preset standard is that the arc melting temperature is too high; The crystallization characteristic value is the ratio between the crystallization area of the crucible substrate and the total surface area of the crucible substrate.

8. The preparation method of the quartz crucible with high stability according to claim 7, characterized in that, If it is determined that the preparation of the target crucible does not meet the preset standard according to the coating quality characterization value and the first preset coating quality characterization value, then according to the magnitude relationship between the coating quality characterization value and the second preset coating quality characterization value, determine whether to increase the spraying pressure or the spraying distance, including: Compare the coating quality characterization value with the first preset coating quality characterization value. If the coating quality characterization value is greater than or equal to the first preset coating quality characterization value, it is determined that the preparation of the target crucible does not meet the preset standard; If the coating quality characterization value is greater than or equal to the first preset coating quality characterization value and less than the second preset coating quality characterization value, increase the spraying pressure according to the difference between the coating quality characterization value and the first preset coating quality characterization value; If the coating quality characterization value is greater than or equal to the second preset coating quality characterization value, increase the spraying distance according to the difference between the coating quality characterization value and the second preset coating quality characterization value.

9. The preparation method of the quartz crucible with high stability according to claim 8, characterized in that, The process for obtaining the coating quality characterization value includes: Use a scanning electron microscope to obtain a cross-sectional image of the coating, and statistically calculate the proportion of the pore area through image software to obtain the porosity; Use a thermal conductivity tester to measure along the coating thickness direction at a preset layer thickness interval to obtain the thermal conductivity gradient; Multiply the porosity by the porosity weight to obtain the first coating evaluation value; Multiply the thermal conductivity gradient by the thermal conductivity gradient weight to obtain the second coating evaluation value; Add the first coating evaluation value and the second coating evaluation value to obtain the coating quality characterization value.

10. A quartz crucible prepared by the preparation method according to any one of claims 1-9, characterized in that, Including: A quartz crucible divided into an outer layer and an inner layer from the outer wall to the inner wall, the thickness ratio of the outer layer to the inner layer is 1:1.5 - 3.0; the area of the crystallization region of the quartz crucible accounts for less than 3% of the total inner wall surface area; the quartz crucible includes 10 parts by weight of quartz sand, 1.5 parts by weight of alumina, and 0.5 parts by weight of sodium carbonate according to parts by weight; The inner wall of the quartz crucible is also coated with a silicon nitride coating, the porosity of the coating is less than 5%, the silicon nitride coating includes silicon nitride and silicon dioxide, and the mass ratio of silicon nitride to silicon dioxide is 50 - 70:4 - 20.

Images