Thermodynamic evaluation of the Nb–O–Zr system

Thermodynamic properties of the ternary system Nb–O–Zr have been evaluated by means of the CALPHAD (CALculation of PHAse Diagrams) method. The pertinent experimental data are surveyed and the thermodynamic models based on the previous assessments of the binary systems Nb–O, Nb–Zr and O–Zr are delineated. The results of our computations indicate that the models describe the zirconium rich portion of the ternary phase diagram satisfactorily, however, in the niobium rich part, the calculations differ from the experimental data and should be verified by new experiments.