PHASE EQUILIBRIA IN THE Ti-Si-B-C QUATERNARY SYSTEM AS A BASIS FOR DEVELOPING NEW CERAMIC MATERIALS

Using the CALPHAD method, a thermodynamic model of the Ti-Si-B-C quaternary system is developed for the first time. Based on calculations of phase equilibria, a way for tetrahedration of this system is proposed. Fragments of the phase diagrams that have not been studied previously are calculated for the boundary ternary systems, with calculations for Si-B-C being performed for the first time. It is concluded that there is no quasiternary eutectic with participation of ZrB(2), B(4)C, and SiC compounds in the Ti-Si-B-C system. It is shown that additions of titanium carbide to the ZrB(2) + B(4)C + SiC mixture should lead to reactions resulting in solid-state formation of graphite (for example, during sintering or hot pressing) or its crystallization as a primary phase during separation from the melt, in a wide range of compositions. It should be taken into account in development of materials from these refractory compounds.