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

The pseudo-ternary Al 2 O 3 -SiO 2 -“V 2 O 3 ” 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-CO 2 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 Al 2 O 3 -corundum + V 2 O 3 -corundum + mullite and V 2 O 3 -corundum + liquid + cristobalite equilibria, in contrast to the V 2 O 3 -corundum + mullite + liquid equilibrium where an effect was evident. For the latter equilibrium, decreased oxygen potential resulted in higher contents of Al 2 O 3 and slightly higher contents of V 2 O 3 in the liquid phase, as well as slightly higher contents of Al 2 O 3 in V 2 O 3 -corundum and mullite.