The structure and diffusion of liquid Al2O3 were investigated by using molecular dynamics methods. Simulations were performed in a basic cube, with periodic boundary conditions, which contained 3000 ions with BKS pair potentials. The structure of the liquid models agreed reasonably well with experiment. The microstructure of the system was analyzed via partial radial distribution functions, coordination number distributions, bond-angle distributions and interatomic distances. Calculations showed that, in a liquid Al2O3 model, with real density of 2.80g/cm3, there existed short-range order dominated by distorted AlO4 tetrahedra; in agreement with Landron’s experiment. The temperature dependence of the self-diffusion constants, D, in the liquid Al2O3 obeyed an Arrhenius law with an activation energy which was close to the experimental one for liquid SiO2 and was close to the calculated figure for diffusion in liquid aluminum silicate. With increasing temperature, it was found that this dependence exhibited a cross-over to one which could be described well by a power law, D  (T-Tc)γ. The critical temperature, Tc, was about 3500K and the exponent, γ, was close to 0.50. The phase transition temperature, Tg, for the Al2O3 system was about 2100K.

Structure and Diffusion Simulation of Liquid Al2O3. V.V.Hoang, S.K.Oh: Physica B, 2004, 352[1-4], 342-52