Phase equilibria investigations and thermodynamic modeling of the PbO-Al₂O₃ system

The PbO-Al₂O₃ system has been extensively studied in literature. In the present study, experimental work was conducted in which equilibria between phases were investigated under air between 600°C and 800°C by X-ray diffraction. Three intermediate compounds reported in literature were confirmed, which are PbAl₁₂O₁₉ (1PbO:6Al₂O₃), PbAl₂O₄ (1:1)and Pb₂Al₂O₅ (2:1). Results support awidely accepted version of the phase diagram in which these compounds exist. On the basis of the results obtained in this study and data considered from literature, a thermodynamic modeling according to the Calphad approach was performed, where all intermediate phases were considered as stoichiometric compounds and where the liquid phase was described by a two-sublattice ionic liquid model. Good agreement has been obtained from thermodynamic optimization in comparison with experimental results.