Chemical gas deposition (CVD) method) method

Silicon and carbon -containing gases have a heat decomposition through high -temperature graphite matrix, and SIC is deposited on the surface of the graphite matrix. The raw materials are trichloronetas (CH3SIC3), silicon chloride, hydrogen, silicon steam, etc. The deposition temperature range is wide, from 1175 ° C to 1775 ° C. The SIC layer generated by this method is very dense, the thickness is uniform, and the general thickness is about 0.1 to 0.3mm. However, the combination of SIC and graphite matrix is a combination of pure machinery, and the combination force is weak. When the temperature changes, the SIC layer is prone to cracking and peeling.

Chemical Qi Evidence Method (CVR)

The raw materials are coke powder and excessive quartz sand or non -fixed silicon powder. Chemical reactions occur when heated to 2000 ° C to generate SIO vapor. SIO steam and carbon -based reactions generate SIC. There is no obvious interface between SIC layers and carbon -based bodies. The combination is very solid. It will not fall off in the case of sudden changes in temperature and high load. Sexual, when used as a sealing material, it is necessary to use resin or CVD method to fill in pores.

Silicon penetration method

This method is also a type of CVR. Under vacuum conditions, heated to 1700-1900 ° C, and directly immersed the carbon matrix into the melted silicone, and the silicon was gradually penetrated into the carbon group, and the response was generated to generate SIC. The raw materials are pure silicon with 99.9999%. SIC layer thickness can reach 3.5mm. After the reaction, the carbon group contains about 17%of the pores of the free silicon filling matrix to make the substrate dense. However, the existence of free silicon reduces the corrosion resistance and high temperature antioxidant performance of silicon graphite.