Thermodynamic description of the La–Co–Fe and Ce–Co–Fe ternary systems

Based on the available experimental data reported in the literature, the La–Co and Ce–Co binary systems were re-assessed thermodynamically using the CALPHAD method in this work. The calculated phase diagrams and thermodynamic properties of the La–Co and Ce–Co binary systems are well consistent with the experimental results. Furthermore, the La–Co–Fe and Ce–Co–Fe ternary systems were calculated by combining the re-assessed La–Co and Ce–Co binary systems in this work with the previous assessments of the La–Fe, Ce–Fe and Co–Fe binary systems. The calculated liquidus projections, isothermal sections and vertical sections in the La–Co–Fe and Ce–Co–Fe ternary systems are in good agreement with the experimental results. The reasonable thermodynamic parameters of the La–Co–Fe and Ce–Co–Fe ternary systems were obtained in this work, which would be fundamental to developing a thermodynamic database of the multi-component RE-TM-Fe alloy systems, and then to designing novel RE₂Fe_17-xTM_x magnets with light rare-earth metals La and Ce.