Ethanol-Water-Derived Sucrose-Coated-Al2O3 for Submicrometer AlON Powder Synthesis

Fluffy and homogenous sucrose‐coated‐γ‐Al2O3 structured precursor was prepared by drying ethanol‐water sucrose/Al2O3 suspension, in which the ethanol content of 85 vol% was optimized. Using the C/Al2O3 mixture pyrolyzed from such precursor with 23.2 wt% sucrose, single‐phase AlON powder was synthesized by two‐step carbothermal reduction and nitridation method at 1550°C for 2 h and 1700°C for another 1.5 h. The particle size of the AlON powder was around 0.6–1.0 μm. Compared with those synthesized by the traditional approaches with mechanical C/Al2O3, Al/Al2O3, or AlN/Al2O3 mixtures, the synthesis temperature was reduced about 50°C, and the AlON powder was fine and exhibited good dispersity. Such superiority of this method was attributed to that the pyrolyzed carbon film on Al2O3 particle greatly restrained Al2O3 coalescence during the thermal treatment.