Thermodynamic analysis of the silicon carbide synthesis in complex metal melts

The Me-Si-C systems which contain metal melt are the basis of a promising technique for growing single crystals of silicon carbide. Such techniques necessitate the search for metal compositions with relatively low melting points, which would preserve the ability to dissolve silicon and carbon in sufficient amounts. The increasing complexity of metal melt compositions based on the elements of the iron subgroup enables to achieve the desired effect. To search new compositions of fusible metal melts, i.e. catalysts of silicon carbide crystals growth, it is advisable to use the liquidus surface of the Fe-(...)-Si-C systems. The aim of this work was to make thermodynamic modeling of the Fe-(...)-Si-C systems to identify opportunities for reducing the metal melt temperature in equilibrium with silicon carbide. The “Phase Diagram” block of the software package “FactSage” (version 6.4) developed by “Thermfact” (Canada) and “GTT Technologies” (Germany) were used for thermodynamic modeling. During this investigation liquidus surfaces of the Fe-Ni-Si-C, Fe-Co-Si-C, Fe-Mn-Si-C and Fe-Ni-Co-Mn-Si-C systems were calculated. Phase diagrams presented in the form of surface liquidus enable not only to determine metal composition with the lowest melting point, but also to visualize the range of concentrations and temperatures for which SiC is the reaction product of metal components. This is especially useful in the mode selection process of growing silicon carbide crystals.