Synthesis and X-ray Diffraction Study of Aluminum γ-Oxonitride Solid Solutions

Samples of a solid solution aluminum oxonitride (γ-AlON) of spinel structure with different ratios of components (Al 2 O 3 and AlN) were prepared by the sol–gel technique combined with high-temperature solid-state synthesis at 1750°C in a nitrogen atmosphere. The X-ray diffraction study of polycrystalline samples was performed by the Rietveld method. It was shown that the crystal structure of γ-AlON can be described by the model of permanent anions. The occupancies of tetrahedral and octahedral positions by aluminum atoms in the cationic sublattice of spinel are less than one, and the vacancies are predominantly located in octahedral positions. The lattice constant of the spinel phase (7.9499 Å) in the sample with 67 mol % of Al 2 O 3 and the near-stoichiometric composition Al 23 O 27 N 5 , almost coincides with early published data. The spinel parameter u slightly depends on the concentration and is equal to ∼0.3810.