Neutron diffraction of γ-aluminium oxynitride

Neutron diffraction expts. were performed on Al oxynitride (Alon) powders with compns. corresponding to 67.5, 73 and 77.5 mol.% Al2O3. The 73 mol.% powder was produced by reacting Al2O3 and AlN powders for 3 h at 1750 Deg. After reaction the resultant powder was ground with a mortar and pestle to eliminate large particles. X-ray diffraction (XRD) of the powder revealed that residual AlN was present. The Alon structure can be described with the const.-anion model. In this case the vacancies in the cation lattice are located almost completely at octahedral sites in the lattice. Neutron diffraction yields approx. the same lattice parameter for the Alons as XRD: 0.7953, 0.7944 and 0.7938 for Alon with a compn. of 67.5, 73 and 77.5 mol.% Al2O3, resp. The spinel parameter of Alon is not or is not very weakly dependent on the compn. of the Alon and is approx. equal to 0.3812. [on SciFinder (R)]