HIGH-TEMPERATURE INTERACTION BETWEEN SILICON AND CARBON

The ETE method was used for the investigation of high-temperature interaction in the silicon-carbon system and for the manufacture of compacted silicon carbide. The samples were ignited after silicon melting, independently of the heating rate. Maximum values of temperature realized in ETE were 2330-2430-degrees-C. The intensity of chemical heat evolution after the melting of silicon depends upon temperature exponentially, with the apparent activation energy equal to 55 +/- 4 kcal/mole. The conclusion was drawn that a limiting stage of the process is the liquid-phase diffusion of carbon in silicon occurring because of a difference in carbon concentration in the melt near the surface of carbon particles and carbide particles. The ETE technique allows both the synthesis of SiC and the manufacture of constructional materials to be accomplished simultaneously. The ETE-manufactured SiC product is represented mainly by its beta-phase. The relative density of the product is about 0.8-0.9.