Phase Relations and Reaction Sintering of Transparent Cubic Aluminum Oxynitride Spinel (ALON)

Abstract

A new isobaric, condensed phase diagram in the region of stability of cubic aluminum oxynitride spinel (ALON) along the pseudobinary AI 2 O 3 ‐AIN composition join is presented, deduced primarily from various analytical measurements and microstructural observations. It is shown that cubic aluminum oxynitride spinel melts incongruently at ≊2050°C and is compositionally centered at ≊35.7 mol% AIN, which is equivalent to the following stoichiometric composition: AI 23 O 27 N 5 or 5AIN·9AI 2 O 3 . Single‐phase ALON material sintered to nearly full density exhibits transparency in visible light.