Thermodynamic Modeling of the C-Co-Mo and C-Mo-Ni Ternary Systems

The C-Co-Mo and C-Mo-Ni systems were assessed by means of the CALPHAD (CALculation of PHAse Diagram) approach. All of the experimental phase diagram and thermodynamic data available from the literature were critically reviewed. The liquid was modeled as substitutional solution phase, while the solid solution phases including (gamma Co), (Ni), (Mo), MoC and Mo2C were described by sublattice model. The M6C and M12C ternary carbides were considered as linear and stoichiometric compounds, respectively. The modeling of C-Co-Mo and C-Mo-Ni systems covers the whole composition and temperature ranges. A set of self-consistent thermodynamic parameters for the C-Co-Mo and C-Mo-Ni systems was finally obtained. Comprehensive comparisons between the calculated and measured phase diagram and thermodynamic data show that the experimental information is satisfactorily accounted for by the present thermodynamic description. The liquidus projection and reaction scheme of the C-Co-Mo and C-Mo-Ni systems were also generated by using the present thermodynamic parameters.