The synthesis of a carbon solid solution in silicon carbide (SiC–C) under “smoldering” self-propagating high-temperature synthesis (SHS) conditions in the presence of titanium dioxide was investigated, and the structure and properties of ceramics obtained by high-pressure sintering were studied. It was established that SiC–TiC composite powder is synthesized from a mixture of thermally expanded graphite (TEG) and silicon with a mass ratio of 1 : 2.7 to 1 : 4 and a titanium dioxide content of 35 wt % at a temperature of 1200°C. The development of “smoldering” SHS in silicon carbide is characterized by nonequilibrium processes in microvolumes associated with the structural state of TEG and gas-transport reactions. The temperature rise in the microvolume caused by the exothermic interaction between TEG and silicon creates favorable thermodynamic conditions for the formation of titanium carbide in the TEG–Si–TiO2 system. X-ray diffraction analysis showed that the lattice parameters of both carbides are lower than those of stoichiometric carbides. Ceramics sintered under high pressure from the synthesized composite powders exhibit high hardness (43.4 GPa) due to dispersion–strain hardening.
Gadzyra et al. (Wed,) studied this question.