A method for locally repairing a degraded quartz crucible and a repaired quartz crucible

Abstract

This invention discloses a method for local repair of downgraded quartz crucibles and the repaired quartz crucible, relating to the field of quartz crucible repair technology. The key technical points include the following steps: classifying the quartz crucibles to be graded according to defect size; classifying quartz crucibles with defect sizes no larger than a preset threshold as repairable C1 grade, and quartz crucibles with defect sizes larger than the preset threshold as C2 grade for providing repair material; removing the defective area of ​​the C1 grade quartz crucible to form a notch; cutting and obtaining repair material from the defect-free area of ​​the C2 grade quartz crucible, the size of the repair material being configured to be larger than the notch size; locally heating the edge of the repair material to be joined to the quartz softening temperature, then pressing the softened repair material into the notch, and after cooling, forming an integral part with the C1 grade quartz crucible. This invention can utilize previously scrapped quartz crucibles, effectively improving the yield of downgraded quartz crucibles and reducing raw material consumption.

Description

Technical Field

[0001] This invention relates to the field of quartz crucible repair technology, and more specifically, to a method for local repair of a degraded quartz crucible and the repaired quartz crucible. Background Technology

[0002] Photovoltaic quartz crucibles are critical consumable components in the Czochralski (CZ) monocrystalline silicon pulling process, and the purity and density of their inner walls directly determine the quality of the pulled silicon ingots. Currently, in the process of producing quartz crucibles using the electric arc method to melt quartz sand, localized defects such as bubbles and black spots often appear on or within the crucible's inner wall due to raw material impurities, environmental factors, or process fluctuations. These defects may expand or contaminate the silicon melt under high-temperature crystal pulling conditions, leading to the quartz crucible being deemed a downgraded or scrap product.

[0003] Currently, the industry's conventional methods for handling downgraded quartz crucibles are either direct scrapping or complete remelting. Direct scrapping results in a serious waste of quartz sand resources and high energy consumption; while complete remelting not only consumes a huge amount of energy, but also easily introduces new defects during secondary melting, resulting in poor economic efficiency and reliability. In addition, there are techniques that use laser vaporization of defects followed by filling with molten quartz sand, but this method is difficult to simulate the original crucible production process, and the filled area often contains a large number of new bubbles, failing to meet the requirements for high-quality crystal pulling.

[0004] Therefore, a new solution is needed to address this problem. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a method for local repair of a degraded quartz crucible and a repaired quartz crucible, so as to solve the problems of difficult repair of degraded crucibles and serious waste of resources in the prior art.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is: a method for local repair of a degraded quartz crucible, comprising the following steps:

[0007] S1. Classify the quartz crucibles to be graded according to the defect size. Classify the quartz crucibles with defect sizes not greater than a preset threshold as repairable grade C1, and classify the quartz crucibles with defect sizes greater than the preset threshold as grade C2 for providing repair materials.

[0008] S2. Remove the defective area of ​​the C1 grade quartz crucible to form a notch, and clean the edges of the notch;

[0009] S3. Cut and obtain repair material from the defect-free area of ​​the C2 grade quartz crucible, wherein the size of the repair material is configured to be larger than the size of the notch;

[0010] S4. The edge of the repair material to be joined is locally heated to the quartz softening temperature, and then the softened repair material is pressed into the notch. After cooling, the repair material and the C1 grade quartz crucible are integrated.

[0011] Preferably, in step S1, the defect size is the diameter of the maximum circumscribed circle of the defect region.

[0012] Preferably, in step S2, the notch is constructed as a circle.

[0013] Preferably, the preset threshold is 50mm.

[0014] Preferably, in step S2, the cleaning is a dry cleaning.

[0015] Preferably, in step S3, the area where the repair material is cut from the C2-grade quartz crucible is at the same or similar horizontal height as the area where the notch is located on the C1-grade quartz crucible.

[0016] Preferably, in step S3, the size of the repair material is 2% to 5% larger than the size of the gap.

[0017] Preferably, in step S4, the local heating is performed using a laser or an oxyhydrogen flame.

[0018] Preferably, after step S4, the method further includes: S5, polishing the joint between the cooled repair material and the C1 grade quartz crucible.

[0019] A quartz crucible, obtained by repairing a degraded quartz crucible using any one of the methods described above.

[0020] Compared with existing technologies, the advantages of the local repair method for downgraded quartz crucibles and the repaired quartz crucibles disclosed in this invention are as follows: By classifying the downgraded quartz crucibles and using their own materials for homogeneous repair, the originally scrapped quartz crucibles can be utilized as resources, effectively improving the yield of downgraded quartz crucibles and reducing raw material consumption. Through precise local hot-melt bonding, the repair material and the C1-grade quartz crucible form a dense and solid integrated structure, ensuring that the repaired C1 quartz crucible can meet the reliability requirements of the high-temperature crystal pulling process. Simultaneously, this process provides clear defect identification and repair material matching specifications, achieving standardization of the repair process and ensuring consistency and repeatability of quality. Attached Figure Description

[0021] 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.

[0022] Figure 1 This is a flowchart illustrating a method for local repair of a downgraded quartz crucible according to an embodiment of this application. Detailed Implementation

[0023] The technical solution of the present invention will now be clearly and completely described through specific embodiments. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0024] Please see Figure 1 The embodiments of this application provide a method for local repair of a degraded quartz crucible, comprising the following steps:

[0025] S1. Classify the quartz crucibles to be graded according to the defect size. Quartz crucibles with defect sizes not exceeding a preset threshold are classified as repairable grade C1, and quartz crucibles with defect sizes exceeding the preset threshold are classified as grade C2 for providing repair material. Specifically, the defect size is the maximum outer diameter of the defect area, and the preset threshold is 50mm. This preset threshold is because experience shows that defect sizes exceeding this size are very likely to cause the crucible body to crack during subsequent cutting, resulting in a low repair success rate.

[0026] S2. Using high-precision cutting equipment (such as laser cutters, waterjet cutters, diamond wire saws, etc.), remove the entire defect area of ​​the C1 grade quartz crucible to form a notch. This notch is cut into a circular shape, so that during subsequent hot-melt bonding and high-temperature use, thermal stress will be evenly distributed along the entire circumference of the notch, eliminating sharp corner areas of stress concentration. This reduces the risk of microcracks or even cracking of the repair interface or quartz crucible due to localized stress concentration during heating, cooling, or use. After removal, the edges of the notch are dry-cleaned, for example, by blowing with dry compressed gas or wiping with a clean, lint-free cloth to remove adhering particles.

[0027] S3. Select a defect-free area at the same or similar horizontal level as the C1 grade crucible notch, and cut a piece of quartz material as the repair material. The size of the repair material is configured to be larger than the size of the notch, preferably 2% to 5% larger than the size of the notch. This configuration provides appropriate material allowance for subsequent hot-pressing to ensure a tight interface.

[0028] S4. Using a laser (e.g., a CO2 laser with a power of 10kW to 20kW) or an oxyhydrogen flame, locally heat the edge of the repair material to be joined, controlling the temperature between 1580℃ and 1650℃, so that the area reaches the quartz softening temperature. At this temperature, the edge of the repair material is in a softened but not melted flow state. The heating time can be adjusted and optimized according to the specific size of the repair material and the heating method, and is not limited here. Subsequently, using a high-temperature resistant suction cup or other clamps, the softened repair material is precisely aligned and pressed into the notch of the C1-grade quartz crucible, and allowed to cool naturally after maintaining a stable position. During this process, the repair material at the softened edge fuses with the C1 quartz crucible through molecular diffusion. After complete cooling, the repair material and the C1 quartz crucible form a dense and strong integrated structure.

[0029] S5. Grind the joint between the cooled repair material and the C1 grade quartz crucible. Grinding can be divided into coarse grinding and fine grinding. Fine grinding is preferably done with a 150-200 grit abrasive. The final surface roughness Ra of the joint is in the range of 0.1μm to 1μm, thereby ensuring the smoothness and flatness of the inner wall of the C1 grade crucible.

[0030] This invention also discloses a quartz crucible, which is repaired using any of the methods described above for the partial repair of a downgraded quartz crucible. It should be noted that, when using the repaired quartz crucible, the highest temperature during a single continuous operation should not exceed 1600℃, and the longest operating time should not exceed 480 hours. Under these conditions, the repaired interface structure is stable, and its performance meets the technical requirements for auxiliary quartz crucibles in the photovoltaic single-crystal pulling process.

[0031] In summary, this invention, by classifying downgraded quartz crucibles and using its own materials for homogeneous repair, enables the resource utilization of previously discarded quartz crucibles, effectively improving the yield rate of downgraded quartz crucibles and reducing raw material consumption. Through precise localized hot-melt bonding, the repair material and the C1-grade quartz crucible form a dense and robust integrated structure, ensuring that the repaired C1 quartz crucible meets the reliability requirements of the high-temperature crystal pulling process. Simultaneously, this process provides clear defect identification and repair material matching specifications, achieving standardization of the repair process and guaranteeing consistency and repeatability of quality.

[0032] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for local repair of a degraded quartz crucible, characterized in that, Includes the following steps: S1. Classify the quartz crucibles to be graded according to the defect size. Classify the quartz crucibles with defect sizes not greater than a preset threshold as repairable grade C1, and classify the quartz crucibles with defect sizes greater than the preset threshold as grade C2 for providing repair materials. S2. Remove the defective area of ​​the C1 grade quartz crucible to form a notch, and clean the edges of the notch; S3. Cut and obtain repair material from the defect-free area of ​​the C2 grade quartz crucible, wherein the size of the repair material is configured to be larger than the size of the notch; S4. The edge of the repair material to be joined is locally heated to the quartz softening temperature, and then the softened repair material is pressed into the notch. After cooling, the repair material and the C1 grade quartz crucible are integrated.

2. The method for local repair of a downgraded quartz crucible according to claim 1, characterized in that: In step S1, the defect size is the diameter of the maximum circumcircle of the defect region.

3. The method for local repair of a downgraded quartz crucible according to claim 1, characterized in that: In step S2, the notch is constructed into a circle.

4. The method for local repair of a downgraded quartz crucible according to claim 2, characterized in that: The preset threshold is 50mm.

5. The method for local repair of a downgraded quartz crucible according to claim 1, characterized in that: In step S2, the cleaning is a dry cleaning.

6. The method for local repair of a downgraded quartz crucible according to claim 1, characterized in that: In step S3, the area where the repair material is cut from the C2 grade quartz crucible is at the same or similar horizontal height as the area where the notch is located on the C1 grade quartz crucible.

7. The method for local repair of a downgraded quartz crucible according to claim 1, characterized in that: In step S3, the size of the repair material is 2% to 5% larger than the size of the gap.

8. The method for local repair of a downgraded quartz crucible according to claim 1, characterized in that: In step S4, the local heating is performed using a laser or an oxyhydrogen flame.

9. The method for local repair of a downgraded quartz crucible according to claim 1, characterized in that: After step S4, the process further includes: S5, polishing the joint between the cooled repair material and the C1 grade quartz crucible.

10. A quartz crucible, characterized in that: The degraded quartz crucible was repaired using the local repair method described in any one of claims 1 to 9.

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