The Al2O3-SiO2-“V2O3” phase diagram at 1873 K

The pseudo-ternary Al₂O₃-SiO₂-“V₂O₃” phase diagram was studied at 1873 K and oxygen partial pressures of 3.4 × 10⁻¹¹, 3.3 × 10⁻¹⁰ and 3.4 × 10⁻⁹ atm. The samples were kept in a CO-CO₂ mixture to control the oxygen potential and quenched in oil after equilibration. The phase compositions of the quenched samples were analyzed using wavelength-dispersive spectroscopy. The analyses were used to construct the phase diagrams. A change in oxygen potential did not profoundly affect the Al₂O₃-corundum + V₂O₃-corundum + mullite and V₂O₃-corundum + liquid + cristobalite equilibria, in contrast to the V₂O₃-corundum + mullite + liquid equilibrium where an effect was evident. For the latter equilibrium, decreased oxygen potential resulted in higher contents of Al₂O₃ and slightly higher contents of V₂O₃ in the liquid phase, as well as slightly higher contents of Al₂O₃ in V₂O₃-corundum and mullite.