Equilibrium phase relationship between SiC and a liquid phase in the Fe-Si-C system at 1523-1723 K

Abstract

Fe-Si melt is a candidate for use as an alloy solvent for rapid liquid phase growth of SiC because of the high solubility of carbon in molten iron. In this work, the equilibrium phase relationship between SiC and the liquid phase of the Fe-Si-C system was studied to determine the optimal composition of a high SiC content solvent. The solubility of carbon in molten silicon was examined and the thermodynamic properties of the liquid phase in the Si-C system were reassessed. The phase relationship between SiC and Fe-Si melt was investigated by the equilibration technique at 1523-1723 K. It was found that Fe-36mol% Si alloy equilibrates with SiC at the corresponding temperatures. The equilibrium phase relationship between SiC and various compositions of Fe-Si melts was studied by using thermodynamic calculations. The results indicated that SiC is far more soluble in iron-rich Fe-Si melt than in silicon-rich melt. The Fe-Si melt of Fe-36 mol% Si composition possessing high SiC solubility should be a suitable solvent for rapid liquid phase growth of SiC. ©2009 The Japan Institute of Metals.