Crystal Phases in the System Al ₂ O ₃ –AlN

Abstract

Fused aluminum oxide containing a small amount of nitrogen (as added aluminum nitride) showed X‐ray powder diffraction patterns similar to the δ‐alumina obtained from the calcination of alumina mouohydrate in dry air. About 1% nitrogen was adequate for complete conversion of the α phase to the δ phase. A fused mixture containing 3.9% nitrogen showed a powder pattern identical to lithium ζ‐alumina.