Effects of Al2O3 phase composition on AlON powder synthesis via aluminothermic reduction and nitridation

Abstract

Abstract Using micro-sized aluminum powder (11 wt.%) and nano-sized Al2O3 powder (89 wt.%) with five different phase compositions, AlON powders were synthesized at different temperatures in flowing-nitrogen atmosphere. Our results suggest that for starting materials with low γ-Al2O3/total Al2O3 ratio R (0 and 0.15), a calcination temperature of 1 750 °C is required to obtain single-phase AlON. This temperature is about 50 °C higher than for other batches starting with larger R values (0.5, 0.85, and 1.0). The AlON powders fabricated from reactants with a high R value in this work show narrower particle size distribution and better particle homogeneity than those prepared from batches with lower R values.