COMPUTER-SIMULATION OF THE STRUCTURE, THERMODYNAMIC PROPERTIES, AND TRANSPORT MECHANISM OF CAF2-AL2O3 MELTS

Molecular dynamics simulations were used to develop ionic models of Ca F2-Al2O3 melts. In each simulation, the model system included about 50 0 ions in a cubic box with periodic boundary conditions. The structura l and thermodynamic properties, electric mobility of different ionic s pecies, and temporal stability of the first coordination shells were a nalyzed, The system was found to exhibit positive deviations from idea lity for energy and small negative deviations for molar volume. Topolo gically, the model structures are fairly loose. The bonds between fluo rine and aluminum ions are weak. Aluminum-oxygen groups are fairly sta ble; as a result, in an applied electric field, aluminum ions entrain oxygen ions toward the cathode al almost all alumina concentrations. S imulated conductivity agrees well with experimental data. Complexation in oxyfluoride melts is discussed in detail.