Surface treatment method for C-C heating element

Abstract

The invention discloses a surface treatment method for a C-C heating element, and relates to a polysilicon production process. In the surface treatment method, the conventional hydrogenation production equipment and new technological parameters are adopted, a layer of simple substance silicon is generated in holes and surfaces of the C-C heating element, and then a SiC film is generated through high temperature diffusion. The surface treatment method has the advantages that: raw materials hydrogen and silicon tetrachloride have high purity, so new impurities cannot be introduced, the generated SIC has stable performance and good electrical performance, the SiC film is difficult to damage or fall off, resists corrosion and erosion and effectively protects the C-C heating element, the service life of the C-C heating element is prolonged to over 4,500 hours from 2,500 hours, and the C-C heating element has good economic use value and has positive function on polysilicon closed-loop continuous stable production.

Description

technical field [0001] The invention relates to a polysilicon production process. The C-C heating element is an important part in the hydrogenation process of the Siemens process polysilicon closed-loop production, which is the by-product SiCl in the production of polysilicon. 4 Convert to SiHCl 3 , where SiHCl 3 It is an important raw material for the production of polysilicon. Especially a method for surface treatment of C-C heating elements. Background technique [0002] The heating element used in the hydrogenation furnace designed by the Russian Institute of Rare Metals is C-C heating element material. The C-C heating element material provided by Russian companies is very expensive, and there are less than 4 domestic manufacturers that can provide this heating element. They only promise C-C The heating element material only has a service life of 2500 hours. And each time after the service life expires, new heating element materials need to be replaced, resulting in ...

AI Technical Summary

Problems solved by technology

The manufacturing process itself determines that the heating element material has internal pore defects. Although the surface coating can prolong its life, the fact proves that this coating is easy to fall off under the condition of alternating cold and hot, and is corroded by the process medium at high temperature. , the life expectancy is greatly reduced

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