Computer simulation of liquid Al2O3

Abstract

Molecular dynamic simulation has been done to determine the dynamic and local structure of liquid alumina at 3000K. Fourteen different systems at densities ranging from 2.5 to 4.5gcm-3 was prepared by compressing the low-density melt. Two kinds of pore aggregation, pore cluster and pore tube, were examined. Clear evidence was found of structural transformation from a tetrahedral to an octahedral network. For a low-density system there was a large pore tube, which involved 93% of oxygen-vacancy-like pores and spread over the whole simulation cell. Conversely, in a high-density system the largest pore tube contained less than 1% of all oxygen-vacancy-like pores. A similar trend also was observed for other pore kinds such as aluminium-vacancy-like pores and large pore clusters. The diffusion constants significantly decreased in the region of the structural transformation. The diffusion mechanism in low-and high-density systems was examined and is discussed here. © 2006 IOP Publishing Ltd.