Computer Modeling of the Local Structure, Mixing Properties,
and Stability of Binary Oxide Solid Solutions
with Corundum Structure

N. N. Eremin, R. A. Talis, and V. S. Urusov

Moscow State University, Moscow, Russia

e-mail: neremin@mail.ru; urusov@geol.msu.ru

Received June 22, 2007

Abstract—An original technique of computer modeling of substitutional solid solutions has been applied to
Al₂O₃Cr₂O₃, Al₂O₃Fe₂O₃, and Fe₂O₃Cr₂O₃ binary systems. The parameters of semiempirical interatomic
potentials were optimized using the experimentally studied structural, elastic, and thermodynamic properties of
pure components. Among point defects, the most energetically favorable ones for all three oxides are Schottky
vacancy quintets. To model solid solutions, 44 1 disordered supercells with M¹:M² cation
ratios of 1 : 5, 1 : 2, 1 : 1, 2 : 1, and 5 : 1 have been constructed in the cation sublattice containing 192 atoms.
The mixing enthalpy and volume, interaction parameters, bulk moduli, and vibrational entropy were found by
minimizing the interatomic interaction energy in supercells with the symmetry P1. Calculations of the Gibbs
energy made it possible to estimate the fields of stability of the Al₂O₃Cr₂O₃ and Al₂O₃Fe₂O₃ solid solutions;
these estimates were compared with the experimental data. Histograms of M–M, M–O, and O–O interatomic
distances were constructed and the local structure was analyzed for the Al_1.0Cr_1.0O₃, Al_1.0Fe_1.0O₃, and
Fe_1.0Cr_1.0O₃ compositions.

PACS numbers: 31.15.Gy, 31.90.+s, 36.20.Ey, 61.43.-j, 61.43.Bn, 61.72.Ji, 62.20.Dc, 67.40.Kh

DOI: 10.1134/S1063774508050052

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