Phase Equilibria in the Quaternary Ti–Si–B–C System as A Basis for Developing New Ceramic Materials

Abstract

Using the CALPHAD approach the thermodynamic model of the quaternary system Ti–Si–B–C was developed and basing on results of calculations of phase equilibria the mode of this system terahedration was proposed. Unstudied elements of phase diagrams were calculated for the boundary ternary systems, with the calculations for Si–B–C being performed for the first time. It was concluded that in the Ti–Si–B–C system the quasiternary eutectic with participation of the ZrB₂, B₄C and SiC compounds doesn’t exist. It was shown that additions of titanium carbide to the ZrB₂ + B₄C + SiC mixture should lead to the reactions yielding graphite precipitation in a solid state (for example, during sintering or hot pressing) or to its precipitation 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.