Phase equilibria investigations and thermodynamic modeling of the PbO-Al2O3 system
Résumé
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 degrees C and 800 degrees C by X-ray diffraction. Three intermediate compounds reported in literature were confirmed, which are PbAl12O19 (1PbO:6A(2)O(3)), PbAl2O4 (1:1) and Pb2Al2O5 (2:1). Results support a widely 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 twosublattice ionic liquid model. Good agreement has been obtained from thermodynamic optimization in comparison with experimental results.