One-step carbothermal reduction and nitridation (CRN) for fast fabrication of fine and single phase AlON powder by using hydrothermal synthesized α-Al₂O₃/C mixture

Glucose and ball-milled α-Al₂O₃ mixed powder was hydrothermal treated to synthesize Al₂O₃/C mixture, which was directly heated to 1700–1750 °C for 10 min holding in N₂. Fine and single phase AlON powders were successfully fast prepared by one-step carbothermal reduction and nitridation (CRN). With aggregation of as-purchased α-Al₂O₃ being effectively disconnected by ball milling, α-Al₂O₃ particles were perfectly coated with carbon by hydrothermal treatment, which inhibited coalescence of Al₂O₃ during heating and enabled fast formation of AlON to further shorten holding duration. As a result, one-step fast fabricated pure AlON powder has fine primary particles with weak interconnections. At 170 rpm, powders were ball-milled to D₅₀ ≤ 1.00 μm for 4 h, and D₅₀ = 0.33 μm for 24 h. Moreover, primary particle size is controllable by adjusting holding time, synthesis temperature and heating speed. One-step CRN method provides a practical way to prepare pure AlON powder with the required primary particles.