We have used the thermodynamic modeling method to study reaction in the system SiO₂ TiO₂ C when excess nitrogen is present. We have established that at temperatures of 1200-1800 K, one can obtain a composite material: a mixture of silicon and titanium carbonitrides, the content of which is determined by the composition of the starting mixtures and the compositions of which are determined by the synthesis temperature. The thermodynamic modeling data are supported by the results of chemical and x-ray analysis of the reaction products in the system SiO₂ TiO₂ C in a stream of nitrogen.