Autowave synthesis of cast aluminum oxynitrides with a high nitrogen content

Aluminum oxynitrides Al₂₂O₃₀N₂ and Al₂₃O₂₇N₅ and a number of Al-O-N solid solutions with a nitrogen content of 2.3 to 6.5 wt % were prepared from (CrO₃-Al-Al₂O₃-AlN) thermite-type mixtures with a high combustion temperature (2950–3200 K) by using the autowave synthesis method. The synthesis was conducted in a hermetically sealed reactor at an initial nitrogen pressure of 4.0 to 8.0 MPa. The aluminum nitride content was demonstrated to influence the nitrogen content in cast aluminum oxynitrides and on their microstructure and phase composition.