Synthesis of nano-scaled α-Al₂O₃ particles by combustion spray pyrolysis

Unagglomerated α-Al₂O₃ powders of 100 to 200nm were synthesized by combustion spray pyrolysis with droplet filtration. The ignition conditions of the oxidizer and fuel were well elucidated by the calculation of partial equilibrium species and thermal analysis. A metal screen filter with 500 mesh was employed to dilute the number concentration of the sprayed droplets. The Reynold's number of the aerosol fluid was kept at the value of 1,200 to keep a short residence time and a laminar flow.