Method for preparing crucible coating for polycrystalline silicon ingot casting and crucible

A crucible coating and polysilicon technology, applied in coatings, polycrystalline material growth, chemical instruments and methods, etc., can solve the problems of reducing the compactness of coatings, low crystallinity of coatings, contamination of silicon ingots, etc. Pollution, good coating stability, and the effect of improving the quality of silicon ingots

Inactive Publication Date: 2017-01-04
CHINA UNITED NORTHWEST INST FOR ENG DESIGN & RES
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

For example, silica sol contains nano-scale silica particles, which will react with silicon melt during ingot casting to form silicon monoxide; while organic substances will decompose or volatilize at high temperatures, which will reduce the overall density of the coating. It is easy to cause a certain degree of impurity pollu

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  • Method for preparing crucible coating for polycrystalline silicon ingot casting and crucible

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preparation example Construction

[0034] A method for preparing a crucible coating for polysilicon ingots according to the invention has the advantages of simple operation, controllable process temperature, uniform spray coating thickness, short baking time, low baking temperature and high yield rate of finished crucibles, and can be prepared to meet requirements The hexagonal boron nitride coating, the specific steps are as follows:

[0035] 1) Ingredients: weigh a certain amount of hexagonal boron nitride;

[0036] The paint sprayed on the inner wall of the crucible includes hexagonal boron nitride. The molecular formula of hexagonal boron nitride is BN. It has a layered structure similar to graphite and has good lubricity, electrical insulation, thermal conductivity and chemical corrosion resistance. The chemical properties are stable and inert to all molten metals. The molded products are easy to machine and have high moisture resistance. The melting point is 3000°C under nitrogen pressure, and sublimates...

Embodiment 1

[0050] In the optimization of various parameter schemes, the amount of hexagonal boron nitride should be optimized towards the direction of increasing the amount. After optimization, the amount of hexagonal boron nitride of the present invention is 100 grams, and the less the amount of high-purity water used, the better. Preferably, according to the weight In percentage terms, the amount of high-purity water in the present invention is 220 grams, and the amount of silica sol used, preferably, in terms of weight percentage, the amount of silica sol in the present invention is 100 grams. Keep the room temperature at 26 ° C and stir evenly for 5 minutes to obtain the required For slurry, keep the temperature of the crucible body to be sprayed at 80°C, and the distance from the spray gun to the surface of the crucible body is 18cm; spray the slurry on the bottom surface of the crucible with a thickness of 0.6mm, and then spray silicon nitride on the side of the crucible, spray The ...

Embodiment 2

[0052] According to the weight percentage, the amount of hexagonal boron nitride is selected as 200 grams, the amount of high-purity water is 440 grams, and the amount of silica sol is 200 grams. Keep the room temperature at 24 ° C and stir evenly for 12 minutes to obtain the required slurry. Keep the crucible body to be sprayed The temperature is 70°C, and the distance from the spray gun to the surface of the crucible body is 15cm. Spray the slurry on the bottom surface of the crucible with a thickness of 0.5mm, and then spray silicon nitride on the side of the crucible with a thickness of 0.3mm. , keep the baking temperature at 200°C, and cool naturally after baking for 1 hour.

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Abstract

The invention discloses a method for preparing a crucible coating for polycrystalline silicon ingot casting. The method includes the following steps that hexagonal boron nitride is weighed and slowly added into a mixed solution of silica sol and high-purity water to be evenly stirred, and needed slurry is prepared, wherein the slurry is prepared from, by weight, 20-23% of hexagonal boron nitride, 53-55% of high-purity water and 23-25% of silica sol; before spraying, the slurry is continuously stirred and kept at the room temperature of 24-28 DEG C, the temperature of a crucible to be sprayed is kept at 60-80 DEG C, the slurry is sprayed on the bottom face of the crucible, and silicon nitride is sprayed on the side face of the crucible; the sprayed crucible is roasted, and the crucible coating for polycrystalline silicon ingot casting is formed on the bottom face of the crucible after roasting. The process is simple, operation is convenient, impurity elements are not introduced, and high compactness of the crucible coating is effectively guaranteed, so that the prepared crucible coating is high in purity, accordingly crucible pollution caused by impurities is effectively inhibited, the coating at the bottom of the roasted crucible is good in stability and high in bonding strength, and the service life of a spoon at the bottom is prolonged.

Description

[0001] 【Technical field】 [0002] The invention belongs to the technical equipment field of polycrystalline silicon ingot production, and in particular relates to a method for preparing a crucible coating for polycrystalline silicon ingot and the crucible. [0003] 【Background technique】 [0004] At present, the absolute advantage in the cost of polycrystalline silicon cells makes it gradually replace the dominant position of monocrystalline silicon cells in the market. In the silicon material solar cell industry, polysilicon ingot casting has become the main ingot casting technology. In the process of polysilicon ingot casting, in order to make the silicon ingot be released from the mold and prevent the reaction between liquid silicon and the crucible made of quartz ceramics at high temperature, it is necessary to make a coating on the inner surface of the crucible, and the coating is required to be of high purity and properties. It is stable and has suitable bonding strength...

Claims

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Application Information

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IPC IPC(8): C30B29/06C30B28/06B05D7/24B05D3/02C09D1/00
CPCC30B29/06B05D3/0254B05D7/24B05D2203/30B05D2518/10B05D2601/20C09D1/00C09D5/18C30B28/06
Inventor 田进刘波波田伟赵俊李军
Owner CHINA UNITED NORTHWEST INST FOR ENG DESIGN & RES
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