Molecular Dynamics Study of CaO–Al2O3Melts

Abstract

Molecular dynamics simulations with Born–Mayer pair potentials taking into account the effective dipole–dipole interaction were used to study CaO–Al₂O₃oxides at 1873 K. In each simulation, the system included about 500 ions in a cubic central box with periodic boundary conditions. The thermodynamic, structural, and topological properties of the system were calculated. The inclusion of the dipole–dipole interaction allowed reasonable agreement with the experimental heats of formation to be achieved. According to the simulation results, all of the oxides have a loose structure. At Al₂O₃contents of up to 50 mol %, the Al ions are predominantly in tetrahedral coordination. In the melts containing ≥25 mol % Al₂O₃ , the Al³⁺subsystem is fully polymerized. The electrical conductivity of the melts exceeds the error of determination only for CaO-rich compositions. The self-diffusion coefficients of the ions are very low.