Feature of infiltration under the action of capillary forces of the silicon melt to a great depth of porous carbon material

The results of X-ray diffraction and electron microscopic studies of composite materials obtained in the process of directional impregnation from bottom to top of carbon bases differing in porosity at a temperature of $\ge$ 1500$^\circ$C with a KR-00 grade silicon melt are considered. Results of in situ observation of the interaction of silicon melt with a porous carbon base. It is shown that an increase in the apparent density of the porous carbon matrix over 1.452 g/cm$^3$ limits the height of silicon melt infiltration; In the transition region, only SiC phases and graphite are present; the silicon melt that enters this region completely enters into solid-phase interaction with carbon. The surface of the largest pores turned out to be covered with a layer of silicon carbide.