Assessment of the quasibinary HfO₂-CaO system

Abstract

The HfO₂-CaO quasibinary system has been evaluated thermodynamically by means of Calphad technique. On the basis of extensive and careful evaluation of published experimental results, the optimization and calculation process has been carried out using Thermo-calc, a powerful, integrated package for thermochemical treatment. With the set of the optimized thermodynamic parameters the phase relationships have been predicted, the results were in good agreement with the experimental measurements. Two sets of phase combinations have been obtained corresponding to the disputes in experiments about the ordering phenomena in the low temperature range. It has been shown that more information is required on the liquidus and ordering behavior in this system.

Keywords

thermodynamics / phase diagram / hafnia / calcia