Martensitic transformation thermodynamic calculation of ZrO2–MgO system

Abstract

The phase transformation of different polymorphs in zirconia is very important for the processing and mechanical properties of zirconia ceramics. In this work, thermodynamic description of ZrO2–MgO system is investigated using the related thermodynamic parameters. Special attention is paid to the calculation of the Gibbs free energy change between tetragonal and monoclinic phases in ZrO2–MgO, namely t → m phase transformation driving force, as a function of composition and temperature. Furthermore, in 8.7 mol% MgO–ZrO2, the equilibrium temperature between tetragonal and monoclinic phases, T0, was obtained as 1107.8 K and martensitic transformation start temperature (Ms) for t → m of this ceramic with a mean grain size of 1.15 mm was also calculated to be as 737.7 K, which is in good agreement with experiment one of 689.5 K with 7.0% residual.