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CN-122010396-A - Method for improving mottle on outer surface of quartz crucible

CN122010396ACN 122010396 ACN122010396 ACN 122010396ACN-122010396-A

Abstract

The invention relates to the technical field of quartz crucible production, and particularly discloses a method for improving the mottle on the outer surface of a quartz crucible, which comprises the following steps of (1) matching granularity of quartz sand, wherein the main grain size interval of outer sand is consistent with the main grain size interval of middle sand, and the proportion of the main grain size interval in the grain size interval of the quartz sand is more than or equal to 30%; and (2) treating the inner surface coating of the mold, namely coating a novel high-temperature-resistant and oxidation-resistant composite coating on the inner surface of the quartz crucible forming mold, wherein the coating is used for fused forming of the quartz crucible after solidification. The method has the beneficial effects that the method is simple to operate, can obviously reduce the spots on the outer surface of the quartz crucible, improves the product quality and the appearance quality, and is suitable for large-scale industrial production.

Inventors

  • Lv Yonglong
  • ZHANG GUOQIANG
  • LI CHEN
  • ZHANG XIAOMING
  • ZHENG XIAOYU
  • WANG JIANXIN

Assignees

  • 宁夏欧晶科技有限公司

Dates

Publication Date
20260512
Application Date
20260123

Claims (10)

  1. 1. A method for improving the mottle on the outer surface of a quartz crucible, which is characterized by comprising the following steps: (1) The granularity of quartz sand is matched, namely the main grain size interval of the outer layer sand is consistent with the main grain size interval of the middle layer sand, and the proportion of the main grain size interval in the quartz sand grain size interval is more than or equal to 30 percent; (2) And (3) coating the inner surface of the mold, namely coating a novel high-temperature-resistant and oxidation-resistant composite coating on the inner surface of the quartz crucible forming mold, wherein the coating is used for fused forming of the quartz crucible after solidification.
  2. 2. The method for improving the mottle on the outer surface of the quartz crucible according to claim 1, wherein in the step (1), the outer layer sand and the middle layer sand are both high-purity quartz sand, and the particle size range of the quartz sand is 70-350 μm.
  3. 3. The method according to claim 1, wherein in the step (1), the main particle size range is one of 212 μm to 250 μm, 180 μm to 212 μm, 150 μm to 180 μm, 125 μm to 150 μm, and 106 μm to 125 μm.
  4. 4. The method for improving the mottle on the outer surface of the quartz crucible according to claim 1, wherein in the step (2), the coating comprises, by mass, 40% -55% of rare earth composite oxide, 10% -18% of two-dimensional nano barrier material, 8% -15% of sintering aid, 15% -25% of boron-silicon composite binder, 1% -3% of interface regulator and the balance deionized water, wherein the coating has a pH value of 3.0-3.3, a density of 1.17-1.20 g/cm 3 and a high temperature resistance of not less than 2400 ℃.
  5. 5. The method for improving the mottle on the outer surface of the quartz crucible according to claim 4, wherein the rare earth composite oxide is La 2 O 3 -CeO 2 solid solution, the two-dimensional nano barrier material is hexagonal boron nitride nano sheet with the thickness of 5-15 nm, the sintering aid is Y 2 O 3 -ZrO 2 composite powder, the boron-silicon composite binder is boron modified silica sol, and the interface regulator is titanate coupling agent.
  6. 6. The method for improving the mottle on the outer surface of the quartz crucible according to claim 5, wherein the molar ratio of La 2 O 3 to CeO 2 is 1:2-1:3.
  7. 7. The method for improving the mottle on the outer surface of the quartz crucible according to claim 5, wherein the mass ratio of Y 2 O 3 is 8% -12%.
  8. 8. The method for improving the mottle on the outer surface of the quartz crucible according to claim 5, wherein the boron modified silica sol consists of B 2 O 3 and SiO 2 , and the mass ratio of B 2 O 3 to SiO 2 is 1:5-1:7.
  9. 9. The method for improving the mottle on the outer surface of the quartz crucible according to claim 1, wherein in the step (2), the coating thickness of the coating is 50 μm-200 μm, and the coating mode is one selected from the group consisting of brushing and spraying.
  10. 10. The method for improving the mottle on the outer surface of the quartz crucible according to claim 1, wherein in the step (2), the curing condition is that the curing temperature is 150-200 ℃ and the curing time is 1.5-2.5 h.

Description

Method for improving mottle on outer surface of quartz crucible Technical Field The invention relates to the technical field of quartz crucible production, in particular to a method for improving the mottle on the outer surface of a quartz crucible. Background The quartz crucible is used as a core auxiliary material for drawing monocrystalline silicon, and the surface quality of the quartz crucible directly determines the growth stability, the electrical property and the final product yield of the monocrystalline silicon, so that the quartz crucible has an irreplaceable position in high and new technology industries such as semiconductors, photovoltaics and the like. Along with the continuous upgrading of the semiconductor chip manufacturing process and the continuous improvement of the photovoltaic module efficiency requirement, the market puts forward more stringent requirements on the surface evenness, purity and appearance consistency of the quartz crucible, and the appearance specks on the outer surface become key technical bottlenecks for restricting the upgrading of quartz crucible products, namely, the specks not only lead to the reduction of the product appearance rating, but also influence the stability of a solid-liquid interface in the monocrystalline silicon drawing process due to unbalanced distribution of a heating field caused by uneven surface microstructure in partial serious cases, finally lead to the rise of the monocrystalline defect rate, and bring remarkable economic loss to downstream enterprises. The existing industrial production process of the quartz crucible mainly comprises the steps of filling high-purity quartz sand with purity more than or equal to 99.99% into a graphite mold according to functional layering (outer layer, middle layer and inner layer), scraping, compacting, melting and forming in a high-temperature induction furnace with temperature above 2000 ℃, cooling, demolding, frosting, cleaning, quality detection and the like, and leaving a factory after forming. Although the existing technology realizes large-scale production, the solution to the defect of the outer surface flower spots still has obvious defects, and a mature and effective technical path is not formed, so that a method with simple and convenient operation and stable effect is needed to be developed so as to solve the problem of the flower spots on the outer surface of the quartz crucible. Disclosure of Invention In view of the above, the invention aims to provide a method for improving the mottle on the outer surface of the quartz crucible, which can obviously reduce the mottle on the outer surface of the quartz crucible, improve the quality and the appearance quality of products and is suitable for large-scale industrial production. The technical scheme of the invention discloses a method for improving the mottle on the outer surface of a quartz crucible, which comprises the following steps: (1) The granularity of quartz sand is matched, namely the main grain size interval of the outer layer sand is consistent with the main grain size interval of the middle layer sand, and the proportion of the main grain size interval in the quartz sand grain size interval is more than or equal to 30 percent; (2) And (3) coating the inner surface of the mold, namely coating a novel high-temperature-resistant and oxidation-resistant composite coating on the inner surface of the quartz crucible forming mold, wherein the coating is used for fused forming of the quartz crucible after solidification. In the step (1), the outer layer sand and the middle layer sand are both high-purity quartz sand, and the particle size interval of the quartz sand is 70-350 mu m. Further, in the step (1), the main particle size range is one of 212 μm to 250 μm, 180 μm to 212 μm, 150 μm to 180 μm, 125 μm to 150 μm, 106 μm to 125 μm. In the step (2), the coating comprises, by mass, 40% -55% of a rare earth composite oxide, 10% -18% of a two-dimensional nano barrier material, 8% -15% of a sintering aid, 15% -25% of a boron-silicon composite binder, 1% -3% of an interface regulator and the balance of deionized water, wherein the coating has a pH value of 3.0-3.3, a density of 1.17-1.20 g/cm 3 and a high-temperature resistance of not less than 2400 ℃. Further, the rare earth composite oxide is La 2O3-CeO2 solid solution, the two-dimensional nano barrier material is hexagonal boron nitride (h-BN) nanosheets with the thickness of 5-15 nm, the sintering aid is Y 2O3-ZrO2 composite powder, the boron-silicon composite binder is boron modified silica sol, and the interface regulator is titanate coupling agent (manufacturer: nanjing Xuanhao new material science and technology Co., ltd., model: NXH-131). Wherein the La 2O3-CeO2 solid solution provides core oxidation resistance and high temperature structural stability to the coating. The melting point of La 2O3 is up to 2315 ℃ and the melting point of CeO 2 is 2600 ℃, so that the melting point of the s